Multiple glazing unit having increased selectivity and use of a substrate for producing such a glazing unit

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MULTIPLE GLAZING WITH INCREASED SELECTIVITY

The present invention relates to a multiple glazing comprising at least one outer pane and one inner pane, the panes being separated by at least one insulating blade and said outer pane having an inner face in contact with the insulating blade.

The present invention thus relates to the field of glazing such as glazing for buildings, intended to close a window and thus ensure separation between an exterior space and an interior space, while allowing the passage of at least part of the window. light and in particular sunlight.

The expression “multiple glazing” within the meaning of the present invention thus denotes a glazing comprising at least two panes, an outer pane and an inner pane, an insulating strip, consisting for example of an air space, a space empty of air, or better still of an inert gas layer, being arranged between these two panes, in contact at least with the inner face of the outer pane.

The strip is said to be “insulating” insofar as it can only slightly conduct heat by conduction. It is therefore not a solid or liquid material.

If this insulating strip is also in contact with the inner face of the inner pane, the multiple glazing thus constitutes a double glazing.

However, it is also possible that the insulating strip itself is divided into two independent parts by a pane. The glazing is then a triple glazing.

Windows within the meaning of the present invention are generally monolithic panes each consisting of a sheet of solid material, in particular glass, or even plastic. They can also be composite panes made up of several sheets of glass.

For the production of the glazing according to the invention, a peripheral frame is also provided on the perimeter of the glazing, at least to maintain the insulating strip between the panes. This frame can also participate in the general rigidity of the glazing.

It is known in the prior art to produce multiple glazings without reinforced thermal insulation. In this case, the insulating strip has the effect of preventing the energy transfer between the two end panes thanks to its extremely reduced thermal conduction property. In addition, the convection in this insulating blade is also extremely reduced.

However, to reduce the penetration of solar thermal radiations and in particular the near infrared towards the interior, the person skilled in the art knows how to produce multiple glazing, known as “solar control”, the outer pane of which is provided on its face facing the insulating strip with a stack of thin layers which essentially allows visible light to pass through and blocks for part near infrared on face 2 of the glazing (face 1 being the face of the outer pane in contact with the outside).

Those skilled in the art are aware of two types of solar control (CS) windows: CS windows by absorption and CS windows by reflection.

A major problem posed by CS windows by absorption resides in the fact that the window re-emits part of the energy that it absorbs on face 2, towards the insulating plate, in an isotropic manner, in the thermal infrared (length wave of the order of 10 iim).

These panes have a thermal re-emission factor q; higher than CS windows by reflection and therefore CS windows by absorption generally have a higher solar factor than CS windows by reflection, even if their energy transmission is as good as that of the latter.

The aim of the invention is to overcome the drawbacks of the prior art by proposing a multiple glazing incorporating an external window CS by absorption but having a lower thermal reemission factor φ, therefore a lower solar factor and consequently a selectivity. bigger.

Another essential aim of the invention is to achieve this result in a simple and inexpensive manner.

The present invention thus relates in its broadest sense to a glazing comprising at least one outer pane and one inner pane, the panes being separated by at least one insulating blade and said outer pane having an inner face in contact with the insulating blade. , characterized in that said outer pane comprises a substrate for solar control by absorption, said inner face of the outer pane in contact with the insulating strip being coated with a stack of low-emissive thin layers.

Thus, the stack of low-emissive thin layers located on the surface of the outer pane in contact with the insulating strip, in a position more inside than the absorbent means, limits the thermal reemission of the absorbent means towards the insulating blade and consequently towards the interior.

This reduction in reemission causes a reduction in the thermal reemission factor φ and thus a reduction in the solar factor of the glazing and consequently an increase in the selectivity of the glazing.

The selectivity obtained is even better than that usually obtained by CS glazing by reflection, without the light transmission decreasing for all that.

According to the invention, the outer pane can have several alternative or cumulative configurations:

In a first variant, said outer pane is monolithic and said solar control substrate is a bulk colored substrate;

In a second variant, said outer pane comprises an absorbent solar control coating comprising a stack of thin absorbent layers;

- In a third variant, said outer pane comprises an absorbent coating comprising a dielectric matrix, said matrix incorporating metallic or semiconductor nano-cermets;

In a fourth variant, said outer pane is a composite pane.

In the second variant, said stack of thin absorbent layers preferably comprises at least one functional absorbent layer based on metal nitride such as niobium nitride.

In the third variant, said dielectric matrix is ​​preferably surrounded by an underlying coating based on dielectric materials and an overlying coating based on dielectric materials.

In the fourth variant, the composite outer pane may comprise an intermediate substrate colored in the mass and / or be electrochromic.

Furthermore, the stack of low-emissive thin layers is preferably a stack comprising at least one reflective metallic functional layer based on silver, each functional layer being surrounded by an underlying coating based on dielectric materials and a coating. overlying based on dielectric materials.

This stack may in particular comprise two reflective metallic functional layers based on silver, in order to make it possible to adjust the reflection in higher frequency ranges.

In addition, said inner pane of the multiple glazing is preferably made of a clear substrate, so as not to unnecessarily penalize the light transmission of the glazing.

The present invention will be better understood on reading the detailed description below of non-limiting embodiments and the attached figures:

• Figure 1 illustrates the solar spectrum in normalized intensity;

• Figure 2 illustrates an example of the absorption of a CS substrate by absorption;

• Figure 3 illustrates an example of the reflection of a CS substrate by reflection;

FIG. 4 illustrates an example of the absorption of a CS substrate by colored absorption in the mass and of the absorption of a clear substrate;

• Figure 5 illustrates an example of the reflection of a low-emissive substrate by reflection;

FIG. 6 illustrates an example of transmission of a CS substrate by colored absorption in the mass coated with a low-emissive stack;

FIG. 7 illustrates a first exemplary embodiment of the invention with a colored monolithic CS substrate coated with a stack of thin basemissive layers;

FIG. 8 illustrates a second exemplary embodiment of the invention with a colored monolithic CS substrate coated with a CS stack by absorption under the stack of low-emissive thin layers;

FIG. 9 illustrates a third exemplary embodiment of the invention with a colored monolithic CS substrate coated with an absorbent coating with a dielectric matrix under the stack of low-emissive thin layers; and FIG. 10 illustrates a third exemplary embodiment of the invention with a multiple outer pane integrating a colored CS substrate, the inner face of the outer pane being coated with a stack of low-emissive thin layers.

It is specified that the proportions between the various elements shown are not respected and the peripheral frame of the glazing has not been shown in Figures 7 to 10 in order to facilitate reading.

FIG. 1 illustrates the intensity of the solar spectrum expressed in normalized intensity (I) as a function of the wavelength (λ in nm).

The wavelength corresponding to the visible light spectrum appears below the abscissa line in the form of a rectangle with a wavy interior.

In this figure 1 also appears in the form of a dotted line the effect provided by an ideal solar control glazing such as those skilled in the art might wish to have. This solar control glazing allows all the intensity of the waves to pass in the visible range but prevents all infrared rays, both near visible and far, from penetrating inside.

This dotted line thus illustrates the ideal selectivity of a glazing.

However, those skilled in the art know that for the moment no solar control glazing has this selectivity.

He knows that the selectivity s = Tl / FS, with:

- light transmission:

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Sfr) Tfr) Vfr) d).

<img file="FR2906832A1_D0002.tif" />

Sfr) Vfr) dk the solar factor, FS = Te + φ with the energy transmission:

<img file="FR2906832A1_D0003.tif" />

<img file="FR2906832A1_D0004.tif" />

Sfr) Tfr) d% the thermal re-emission factor q, being a function of absorption and emissivity

S being the solar spectrum, T the transmittance of the glazing and V the sensitivity of the human eye.

Those skilled in the art are currently aware of two types of solar control (CS) windows: CS windows by absorption and CS windows by reflection.

These panes are generally the outer panes of solar control panes.

FIG. 2 illustrates a diagram for measuring the absorption coefficient, in% as a function of the wavelength (λ in nm), of a CS substrate by known absorption, in this case that of the substrate marketed under the name Cool Lite ST by SAINT-GOBAIN GLASS, 6 mm thick, mounted in double glazing by association with a clear 6 mm inner pane, these panes being separated by an insulating strip at 90% argon / 10 air with a thickness of 15 mm.

This substrate of the outer pane is coated with an absorbent coating comprising a stack of thin absorbent layers comprising an absorbent functional layer based on niobium nitride framed by nitrided coatings.

The double glazing has a Te of approximately 37%, and a φ of approximately 8.5% and consequently an FS of approximately 45.5%.

Ideally, this substrate would have the lowest possible absorption in the visible light range and the highest possible in the infrared, but this is not the case.

FIG. 3 illustrates a diagram for measuring the reflection coefficient, in% as a function of the wavelength (λ in nm), of a CS substrate by known reflection, in this case that of the substrate marketed under the name SKN 172 by SAINT-GOBAIN GLASS, 6 mm thick, mounted in double glazing by association with a clear 6 mm inner pane, these panes being separated by an insulating strip at 90% argon / 10 d ' air with a thickness of 15 mm.

This substrate of the outer pane is coated with a reflective coating comprising a stack of reflective thin layers comprising two reflective metallic functional layers based on silver, each functional layer being surrounded by an underlying coating based on dielectric materials, in the occurrence of oxide, and an overlying coating based on dielectric materials, in this case oxide.

The double glazing has a T_E about 36%, and a q; of about 4.5% and therefore an FS of about 40.5%, ultimately better than that of the absorbent substrate below, in terms of selectivity.

Ideally, this substrate would have the lowest possible reflection in the visible light range and the highest possible in the infrared, but this is not the case.

FIG. 4 illustrates a diagram for measuring the reflection coefficient, in% as a function of the wavelength (λ in nm), on the one hand in dotted lines of a CS substrate by known absorption, in this case that of the substrate marketed under the name Parsol Green by the company SAINT-GOBAIN GLAS S (hereinafter “PG”) and on the other hand, for comparison, in solid lines, of a clear substrate marketed under the name Planilux by the company SAINT-GOBAIN GLASS (hereinafter “PLX”).

In order to prevent an external window pane CS from re-emitting part of the energy that it absorbs towards the insulating strip in a glazing, the present invention thus proposes that the external solar control window by absorption is coated, on its face in contact with the glass insulating strip, a stack of thin low-emissive layers in contact with the insulating strip.

In doing so, the reemission towards the insulating plate is reduced, the thermal reemission factor is thus reduced and the solar factor is then reduced, which tends to increase the selectivity at identical light transmission.

FIG. 5 illustrates a diagram for measuring the reflection coefficient, in% as a function of the wavelength (λ in nm), of a low-emissive substrate by known reflection, in this case that of the substrate marketed under the name Planitherm Futur Neutre by the company SAINT-GOBAIN GLASS (hereinafter "PLT"), with a thickness of 6 mm, mounted in double glazing by association with a clear interior glass of 6 mm, these panes being separated by an insulating strip at 90% argon / 10 air with a thickness of 15 mm.

The substrate of the outer pane is coated with a reflective coating comprising a stack of reflective thin layers comprising a reflective metallic functional layer based on silver. It has the configuration similar to that of Example 4 of European patent application EP 718 250, with in addition a top coating for mechanical protection.

The table below summarizes the values ​​measured for double glazing in which the outer pane has a thickness of 6 mm, the inner pane has a thickness of 6 mm, these panes being separated by an insulating strip of 15 mm made up of 90% of argon and 10% air.

<td></td><td>PG / PLX</td><td>SKN-172 / PLX</td><td>PLT / PLX</td><td></td>

<td>T_L</td><td> 65,00%</td><td> 64,7</td><td> 77</td><td> 63,4</td>

<td>T_e</td><td> 36,50%</td><td> 35,8</td><td> 49</td><td> 31</td>

<td>Qi</td><td> 8</td><td> 4,8</td><td> 6,3</td><td> 5</td>

<td>FS</td><td> 44,5</td><td> 40,6</td><td> 55,4</td><td> 36</td>

<td>s</td><td> 1,45</td><td> 1,6</td><td> 1,4</td><td> 1,75</td>

The last column of the above table corresponds to a configuration where the outer pane consists of a substrate PG on which the low-emissive stack PLT has been deposited.

FIG. 6 illustrates a diagram for measuring the transmission coefficient, in% as a function of the wavelength (λ in nm), of this configuration.

This configuration is, moreover, illustrated in FIG. 7.

In this figure, a multiple glazing (10) comprises an outer pane (20) and an inner pane (40) separated by an insulating strip (30). The incident solar radiation is represented by the double arrow to the left of the glazing.

The glazing thus has four faces, numbered from 1 to 4 starting from the outside inwards and the insulating strip is in contact with the faces 2 and 3.

The outer pane (20) consists of a substrate (22) for solar control by absorption colored in the mass PG, this substrate being coated on its inner face 2 with a stack of low-emissive thin layers (29) PLT.

The selectivity of 1.75 obtained with this solution is much better than that of double glazing based on PG (2^e column).

The PLT stack with a single functional silver-based layer makes it possible to obtain a low-emissivity character sufficient to greatly reduce the energy re-emission of the CS substrate by absorption.

The light transmission of the 4^e column is high and is not very altered by the deposition of the low-emissive stack because the latter is very neutral in the part of the visible spectrum. The energy transmission is mainly limited by the CS substrate by absorption. The solar factor and selectivity are thus as good, or even slightly improved, compared to those of a glazing incorporating a CS stack by reflection based on SKN-172 (3^e column).

The solution according to 5^e column is also less expensive to manufacture than the one according to 3^e column.

Another solution consists, as illustrated in FIG. 8, in using a solar control substrate (22) coated with an absorbent coating comprising a stack of thin absorbent layers (24), in particular a stack of thin absorbent layers (24) comprising at the same time. at least one absorbent functional layer based on metal nitride such as niobium nitride, such as for example a stack of the Cool Lite ST type. In the illustrated configuration, the absorbent thin film stack (24) is deposited on a colored substrate of the PG type, but it could well be deposited on a clear substrate of the PLX type.

Another solution consists, as illustrated in FIG. 9, in using a solar control substrate (22) coated with an absorbent coating comprising a dielectric matrix (26), said matrix incorporating metallic or semiconductor nano-cermets, in order to make it possible to achieve a very selective absorption in the near-IR by plasmon resonance effect, with an adjustable wavelength peak depending on the material.

It is thus possible to use, for example, ITO nano-cermets deposited in a dielectric matrix, this matrix being moreover, preferably, framed by an underlying coating based on dielectric materials and an overlying coating based on dielectric materials.

In the configuration illustrated in FIG. 9, the absorbent coating comprising a dielectric matrix (26) is deposited on a colored substrate of the PG type, but it could quite well be deposited on a clear substrate of the PLX type.

Another solution consists, as illustrated in FIG. 10, in using a composite outer pane (20), here consisting of a laminated pane comprising two sheets of glass separated by an intermediate substrate (28).

Here, the interlayer substrate (28) is of PVB and is colored in the mass.

The glazing thus has six faces, numbered from 1 to 6 starting from the outside towards the inside, the intermediate substrate (28) colored in the mass is in contact with the faces 2 and 3 and the insulating strip (30) is in contact with faces 4 and 5.

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Another solution, not illustrated, consists in using an electrochromic composite outer pane, consisting of a laminated pane comprising two sheets of glass separated by an intermediate substrate (28), an electrochromic system being interposed between the substrate and the second pane starting from from the outside.

In this case, when the electrochromic system is in colored mode, it absorbs part of the incident radiation and the low-emissive stack prevents the re-emission towards the insulating plate of part of the energy absorbed by the coating and therefore prevents the re-emission of this energy inwards.

The present invention is described in the above by way of example. It is understood that a person skilled in the art is able to produce different variants of the invention without, however, departing from the scope of the patent as defined by the claims.