Coated substrate for solar control

Abstract

The invention relates to substrates, in particular to transparent substrates, optionally colored, coated with an infrared-reflecting layer and capable of being used as glazing in buildings or in vehicles. Said coated substrates are made up of the combination of a glass substrate in which the composition has a redox of less than 15%, characterized by infrared reflection RIR.sub.V so that RIR.sub.V1.087*TL.sub.V, wherein TL.sub.V is the light transmission of the glass, and an infrared reflecting layer characterized by light transmission TL.sub.C so that TL.sub.C1.3*TIR.sub.C, wherein TIR.sub.C is the infrared transmission of the layer.

Claims

1. A transparent substrate coated with an infrared-reflecting layer, wherein the substrate is a glass comprising a composition which has a redox lower than 15%, characterized by an infrared reflection RIR.sub.V between 780 and 2500 nm such that RIR.sub.V1.087*TL.sub.V, TL.sub.V being the light transmission of the glass between 380 and 780 nm, and in that the infrared-reflecting layer is characterized by a light transmission TL.sub.C between 380 and 780 nm such that TL.sub.C1.3*TIR.sub.C, TIR.sub.C being the infrared transmission of the layer between 780 and 2500 nm.

2. The coated substrate as claimed in claim 1, wherein the substrate is a glass characterized by an infrared reflection RIR.sub.V such that RIR.sub.V1.087*TL.sub.V+5.

3. The coated substrate as claimed in claim 1, characterized by an infrared reflection RIR.sub.V such that RIR.sub.V0.510*TL.sub.V+53.

4. The coated substrate as claimed in claim 1, wherein the glass of the substrate has a composition that comprises, in a content expressed in percentage by total weight of glass: TABLE-US-00019 Total iron (expressed in the form of Fe.sub.2O.sub.3) 0.002-0.06%; and Cr.sub.2O.sub.3 0.0001-0.06%.

5. The coated substrate as claimed in claim 1, wherein the glass of the substrate has a composition that comprises, in a content expressed in percentages by total weight of glass: TABLE-US-00020 Total iron (expressed in the form of Fe.sub.2O.sub.3) 0.002-0.06%;.sup. Cr.sub.2O.sub.3 0.0015-1%; Co 0.0001-1%.

6. The coated substrate as claimed in claim 1, wherein the glass of the substrate has a composition that comprises, in a content expressed in percentages by total weight of glass: TABLE-US-00021 Total iron (expressed in the form of Fe.sub.2O.sub.3) 0.02-1%; Cr.sub.2O.sub.3 0.002-0.5%; Co 0.0001-0.5%.

7. The coated substrate as claimed in claim 1, wherein the glass of the substrate has a composition that comprises, in a content expressed in percentages by total weight of glass: TABLE-US-00022 Total iron (expressed in the form of Fe.sub.2O.sub.3) 0.002-1%; Cr.sub.2O.sub.3 0.0010-0.5%; Co 0.0001-0.5%; Se 0.0003-0.5%.

8. The coated substrate as claimed in claim 1, wherein the infrared-reflecting layer is characterized by an infrared reflection RIR.sub.C of value comprised between or equal to 0.5*(1AIR.sub.C) and 0.86*(1AIR.sub.C).

9. The coated substrate as claimed in claim 1, wherein the infrared-reflecting layer is characterized by an infrared reflection RIR.sub.C of value higher than 0.86*(1AIR.sub.C) and lower than or equal to 0.97*(1AIR.sub.C).

10. The coated substrate as claimed in claim 1, wherein the infrared-reflecting layer is characterized by an infrared reflection RIR.sub.C of value higher than 0.97*(1AIR.sub.C).

11. The coated substrate as claimed in claim 1, wherein the infrared-reflecting layer is a multilayer stack comprising n functional layers based on an infrared-reflecting material, with n1, and n+1 dielectric coatings such that each functional layer is flanked by dielectric coatings.

12. The coated substrate as claimed in claim 11, wherein the functional layers of the infrared-reflecting layer are silver-based.

Description

EXAMPLES 1 TO 18 AND COMPARATIVE EXAMPLES C1 TO C18

(1) Highly selective layers, according to the invention and furthermore respecting the relationship RIR.sub.C>0.97*(1AIR.sub.C), have been combined with different classes, certain of which, not according to the invention (referenced comp-), have an infrared reflection RIR.sub.V lower than 1.087 times their light transmission TL.sub.V, and others, according to the invention (referenced inv-), have an infrared reflection RIR.sub.V higher than or equal to 1.087 times their light transmission TL.sub.V. For double glazings, simulated values of light transmission, solar factor, selectivity and total absorption are given in table A for combinations with layer A and in table B for combinations with layer B.

(2) In order to be able to easily compare the properties of the glazings according to the invention and not according to the invention of equivalent TL, the thickness of the substrate made of glass not according to the invention coated with the layer was engineered by simulation. This approach is valid because the initial TL differences were minimal.

(3) These results show that the combined use of a glass having an infrared reflection such that RIR.sub.V1.087*TL.sub.V and a layer satisfying the relationship TL.sub.C1.3*TIR.sub.C, and the relationship RIR.sub.C>0.97*(1AIR.sub.C), provides, at equivalent TL, a decrease in the solar factor and an increase in selectivity, or at the very least an unchanged selectivity and solar factor, at the same time as a very significantly lower absorption. These combinations may advantageously be used for anti-solar applications.

EXAMPLE 19 AND COMPARATIVE EXAMPLE C19

(4) Example 19 and Comparative Example C19 of Table C demonstrate inter alia the advantage of the present invention in terms of light reflection from the glass side, i.e. seen from the exterior. To be noted for this table: the absorption Abs VR+C is given according to standard ISO9050:2003.

(5) Example 19 shows that via the combination of a substrate made of glass according to the invention and an infrared-reflecting layer according to the invention, it is possible to achieve properties similar to already known structures (C 19), but while avoiding too high an exterior light reflection (RL out) (.sup.10% instead of .sup.18%). This combination therefore provides a selective product of low light reflection and of neutral color, having an absorption that is low enough to avoid the need to temper the glass (commonly accepted typical limit: 40-45%). The production of the layer on the colored glass of Example 19 is easier, and therefore advantageous for the yield and cost of production, because the color of the substrate allows the deviation of color of the layer to be attenuated and thus a better color uniformity to be obtained.

EXAMPLE 20

(6) Example 20 of Table C demonstrates the advantage of combining highly selective layers that offer a light transmission on standard clear glass of about 50% with a blue colored glass according to the present invention, to obtain a product with a light transmission of about 40% (or less), a light-transmission zone in which there are at the present time few highly selective products and that it is difficult to achieve with conventional colored or clear substrates, without increasing exterior light reflection or absorption. This product obtained according to the invention has for its part an absorption that is low enough to avoid the need to temper the glass, a high selectivity and a low to average exterior light reflection, this being highly appreciated.

EXAMPLE 21 AND COMPARATIVE EXAMPLE 21

(7) In Table D, Example 21 shows that by virtue of the combination of a substrate made of glass according to the invention and an infrared-reflecting layer characterized by an infrared reflection RIR.sub.C such that RIR.sub.C>0.97*(1AIR.sub.C), it is possible to achieve properties similar to already known structures (C 21), mainly in terms of light transmission, but while avoiding too high an exterior light reflection (.sup.8% instead of .sup.31%), while decreasing solar factor and improving selectivity, and while retaining a glazing that does not need to be tempered (total absorption=40).

EXAMPLES 22 TO 35 AND COMPARATIVE EXAMPLES C22 TO C35

(8) Various layers according to the invention have been combined with different glasses, certain of which, not according to the invention (referenced comp-), have an infrared reflection RIR.sub.V lower than 1.087 times their light transmission TL.sub.V, and others, according to the invention (referenced inv-), have an infrared reflection RIR.sub.V higher than or equal to 1.087 times their light transmission TL.sub.V. For double glazings, simulated values of light transmission, solar factor, selectivity and total absorption are given in Table E.

(9) In order to be able to easily compare the properties of the glazings according to Examples 25 to 29 and Comparative Example C25 to C29 of equivalent TL, the thickness of the substrate made of glass not according to the invention coated with the layer was engineered by simulation. This approach is valid because the initial TL differences were minimal.

(10) Combinations according to the invention with layers C, D and E will generally rather be used for solar-control applications. Solar factor is slightly increased or similar with glasses according to the invention, but total absorption is clearly less.

(11) Combinations according to the invention with layers F and G will generally rather be used for low-emissivity applications. The solar factor is greatly increased with glasses according to the invention, thus increasing the supply of free energy, and the total absorption is clearly decreased.