Laminated glazing for solar control

Abstract

The invention relates to laminated glazing comprising a substrate, in particular a transparent substrate, optionally colored, coated with an infrared-reflecting layer and capable of being used as glazing in buildings or in vehicles. The coated substrate is made up of the combination of a glass substrate in which the composition has a redox of less than 15%, characterized by infrared reflection RIRV so that RIRV1.087*TLV, wherein TLV is the light transmission of the glass, and an infrared reflecting layer characterized by light transmission TLC so that TLC1.3*TIRC, wherein TIRC is the infrared transmission of the layer.

Claims

1. A laminated glazing comprising a transparent substrate coated with an infrared-reflecting layer, wherein: the substrate is a glass the composition of which has a redox lower than 15%, and the glass has 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 the infrared-reflecting layer has 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 laminated glazing of claim 1, wherein the substrate is a glass having an infrared reflection RIR.sub.V such that RIR.sub.V1.087*TL.sub.V+5.

3. The laminated glazing of claim 1, wherein the substrate is a glass having an infrared reflection RIR.sub.V such that RIF.sub.V0.510*TL.sub.V+53.

4. The laminated glazing of claim 1, wherein the glass of the substrate has a composition that comprises, in a content expressed in percentage by total weight of glass: 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 laminated glazing of claim 1, wherein the glass of the substrate has a composition that comprises, in a content expressed in percentages by total weight of glass: total iron, expressed in the form of Fe.sub.2O.sub.3: 0.002-0.06%; Cr.sub.2O: 0.0015-1%; and Co: 0.0001-1%.

6. The laminated glazing of claim 1, wherein the glass of the substrate has a composition that comprises, in a content expressed in percentages by total weight of glass: total iron, expressed in the form of Fe.sub.2O.sub.3: 0.02-1%; Cr.sub.2O.sub.3: 0.002-0.5%; and Co: 0.0001-0.5%.

7. The laminated glazing of claim 1, wherein the glass of the substrate has a composition that comprises, in a content expressed in percentages by total weight of glass: 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%; and Se: 0.0003-0.5%.

8. The laminated glazing of claim 1, wherein the infrared-reflecting layer has an infrared reflection RIR.sub.C higher than to 0.5*(1AIR.sub.C).

9. The laminated glazing of claim 1, wherein the infrared-reflecting layer has an infrared reflection RIR.sub.C higher than 0.76*(1AIR.sub.C).

10. The laminated glazing of 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.

11. The laminated glazing of claim 10, wherein the one or more functional layers of the infrared-reflecting layer are silver-based.

Description

EXAMPLES 1 TO 18 AND COMPARATIVE EXAMPLES C1 TO C18

(1) 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. Simulated values of the light transmission and reflection, colors in transmission and in reflection, solar factor, selectivity and total absorption of the laminated glazings are given in Table A.

(2) These results show that the combined use of a glass having an infrared reflection such that RIR.sub.V1.087*TL.sub.V and of a layer respecting the relationship TL.sub.C1.3*TIR.sub.C leads, at equivalent TL, to a decrease in solar factor, or at the very least a solar factor that is similar or little increased, at the same time as a lesser absorption. These combinations may therefore advantageously be used for solar-control or anti-solar glazings.

(3) The examples including the layers A, B, or C, show that the combined use of a glass having an infrared reflection such that RIR.sub.V1.087*TL.sub.V and of a layer respecting the relationship TL.sub.C0.76*TIR.sub.C leads, at equivalent TL, to a decrease in solar factor at the same time as a lesser absorption, in all circumstances.

(4) The examples including the layer D furthermore show that the combined use of a glass having an infrared reflection such that RIR.sub.V1.087*TL.sub.V and of a layer characterized by an infrared reflection RIR.sub.C in the range RIR.sub.C>0.5*(1AIR.sub.C) and RIR.sub.C0.76*(1AIR.sub.C) leads, at equivalent TL, to only a small increase in the solar factor (of about at most 5%), which is acceptable in certain circumstances, but again with the benefit of a lesser absorption.

COMPARATIVE EXAMPLES C19 TO C24

(5) A layer not according to the invention was combined with various glasses, certain of which were not according to the invention (referenced comp-) and others of which were according to the invention (referenced inv-). Simulated values of the light transmission and reflection, colors in transmission and in reflection, solar factor, selectivity and absorption of the laminated glazing are given in Table B.

(6) These comparative examples show that the combined use of a glass having an infrared reflection such that RIR.sub.V1.087*TL.sub.V and of a layer not respecting the relationship TL.sub.C1.3*TIR.sub.C leads, at equivalent TL, to a clear increase in the solar factor (of about 20%) and to a clearly decreased selectivity, this making such glazings unsuitable for solar-control applications.