LAMINATED GLAZING HAVING LOW LIGHT TRANSMISSION AND HIGH SELECTIVITY

Abstract

A laminated glazing includes two transparent substrates which are separated by a lamination interlayer, and intended for fitting out buildings or vehicles. One of the transparent substrates is coated with a functional coating capable of acting on solar radiation and/or infrared radiation, and a low emissivity (so-called “low E”) coating is provided on one of the faces of the second substrate.

Claims

1. A laminated glazing comprising first and second transparent substrates which are separated by a lamination interlayer, each of the first and second transparent substrates comprising two main faces, the first transparent substrate being coated on one of its two main faces with a functional coating capable of acting on the solar radiation and/or infrared radiation, said functional coating comprising at least one metallic functional layer, wherein at least one main face of the second substrate comprises a low emissive coating, said low emissive coating comprising at least one low emissive layer between two dielectric coatings.

2. The laminated glazing according to claim 1, wherein the low emissive coating of the second substrate comprises: a first dielectric coating, a low emissivity layer, chosen from transparent conductive oxides and Ti, Zr or Hf nitrides, a second dielectric coating.

3. The laminated glazing according to claim 1, wherein the low emissive coating is provided on face 4, and the functional coating is deposited on face 2 of the laminated glazing, wherein faces of the glazing are numbered from the exterior towards the interior of the glazing.

4. The laminated glazing according to claim 1, wherein the functional coating of the first substrate comprises one or more metal functional layers, each deposited between two dielectric coatings.

5. The laminated glazing according to claim 1, wherein the functional coating of the first substrate comprises, starting from the substrate: a lower dielectric coating, a metallic functional layer, an intermediate dielectric coating, a metallic functional layer, an upper dielectric coating.

6. The laminated glazing according to claim 1, wherein the metallic functional layer of the functional coating of the first substrate is a silver-based layer.

7. The laminated glazing according to claim 1, wherein the dielectric coatings of the coating of the second substrate, have thicknesses between 5 and 100 nm.

8. The laminated glazing according to claim 1, wherein one of the two coatings comprises an absorbing layer.

9. The laminated glazing according to claim 8, wherein a thickness of the absorbing layer is between 2 and 100 nm.

10. The laminated glazing according to claim 1, wherein the laminated glazing has a light transmission of between 25 and 44%.

11. The laminated glazing according to claim 1, wherein the functional coating of the first substrate comprises an absorbing layer.

12. The laminated glazing according to claim 11, wherein the functional coating of the first substrate comprises, starting from the substrate: a lower dielectric coating, a metallic functional layer, an intermediate dielectric coating, a metallic functional layer, an upper dielectric coating, the intermediate dielectric coating comprising an absorbing layer.

13. The laminated glazing according to claim 11, wherein the low emissive coating of the second substrate comprises a transparent conductive layer.

14. The laminated glazing according to claim 11, wherein the first and second substrates are made of glass or of polymer organic material.

15. The laminated glazing according to claim 14, wherein the first and second substrates are made of clear glass.

16. A method for manufacturing a glazing according to claim 1, wherein the functional and low emissive coatings are deposited by magnetron cathode sputtering.

17. The laminated glazing according to claim 7, wherein the dielectric coatings of the coating of the second substrate, have thicknesses between 15 and 80 nm.

18. The laminated glazing according to claim 9, wherein the thickness of the absorbing layer is between 4 and 50 nm.

19. The laminated glazing according to claim 10, wherein the laminated glazing has a light transmission of between 30 and 40%.

20. The laminated glazing according to claim 14, wherein the glass is soda-lime-silica glass.

Description

EXAMPLES

I. Functional coatings

[0229] Functional coatings (RF1, RF2) are deposited on substrates made of clear soda-lime glass with a thickness of 4 mm.

[0230] Table 1 below summarizes the characteristics related to the thicknesses of the different layers constituting the functional coatings. In the laminated glazing, the coated face will constitute the interior face of the first substrate, i.e., face 2 of the laminated glazing.

[0231] The thicknesses of the layers are physical thicknesses, and are expressed in nm.

TABLE-US-00001 TABLE 1 Nature RF1 RF2 RDS Si.sub.3N.sub.4 32 40 ZnO 6 4 blocker NiCr 0.2 1 CF Ag 7 10 RDInt b ZnO 6 4 Si.sub.3N.sub.4 46 CA NbN — 6 RDInt a Si.sub.3N.sub.4 72 32 ZnO 6 4 blocker NiCr 0.2 1 CF Ag 8 8 RDI ZnO 6 4 Si.sub.3N.sub.4 18 24 SUB Glass 4 4 RDS = upper dielectric coating; CA = absorbing layer; CF = functional layer; RDInt = Intermediate dielectric coating; RDI = Lower dielectric coating; SUB = Substrate

Nature of the Layers

[0232] The functional metal layers (CF) are layers based on silver (Ag). The blocking layers are metallic layers made of nickel-chromium alloy (NiCr). The dielectric coatings of the functional coatings comprise barrier layers and stabilizing layers. The barrier layers are based on silicon nitride, doped with aluminum (Si.sub.3N.sub.4: A1) or based on a mixed zinc and tin oxide (SnZnOx). The stabilizing layers are made of zinc oxide (ZnO).

[0233] When the absorbing layer is inserted into the functional coating, it is preferably based on nitride, particularly NbN.

[0234] The layers are deposited by sputtering (called “magnetron cathode” sputtering).

II. Low E coatings

[0235] Low E coatings are deposited on clear soda-lime glass substrates having a thickness of 4 mm. The coated face will constitute the exterior face of the second substrate, i.e., face 4 of the laminated glazing.

[0236] When the functional coating is the RF1 stack above, the low E coating starting from the substrate, is: Si.sub.3N.sub.4 (25 nm)/TiN (23 nm)/Si.sub.3N.sub.4 (25 nm)

[0237] It has an emissivity of 35%.

[0238] When the functional coating is the RF2 stack above, the low E coating starting from the substrate is: Si.sub.3N.sub.4 (25 nm)/ITO (95 nm)/SiO.sub.2 (72 nm)

[0239] It has an emissivity of 20%.

III. Configuration of the laminated glazings

[0240] A first coated substrate of a functional coating (RF) on face 2 and a second coated substrate of a low E coating on face 4 have been assembled in the form of laminated glazing, by means of a traditional laminating interlayer.

[0241] The laminated glazings therefore have a typical structure:

[0242] First substrate/RF/laminating interlayer/second substrate/Low E

V. “Solar Control” and Colorimetry Performance

[0243] Table 2 below lists the main optical characteristics of the laminated glazings obtained.

TABLE-US-00002 TABLE 2 Functional R R Low E Material Position Nature Position Nature TL % a*T b*T Rext % a*Rext b*Rext Rint % a*int b*int g % TE REext S Ref. 1 Face 2 RF 1 none 69 −2.4 0.2 13 −1.3 −0.7 9 −3.1 0.6 50 43 28 1.38 Ref. 2 Face 2 RF 2 none 35 −3.3 0.2 15 −1.4 −3.4 15 0.0 1.1 34 22 26 1.01 Inv. 1 Face 2 RF 1 Face 4 TIN 35 −4.1 −1.5 15 −1.7 −5.8 16 0.6 2.1 28 19 29 1.23 Inv. 2 Face 2 RF 2 Face 4 ITO 35 −3.0 1.0 15 −1.5 −4.0 13 −1.7 −2.7 30 22 26 1.17

[0244] Comparing Inv.1 with Ref.1 and Ref.2, it can be seen that, thanks to a high TL functional coating and an absorbing low E layer, a laminated glazing is obtained having a light transmission within the target of 30 to 40%, a low interior and exterior light reflection, respectively 16 and 15%, and improved selectivity compared to Ref. 2 that has the same TL.

[0245] The TE was able to be reduced relative to Ref. 1 and Ref. 2.

[0246] Comparing Inv. 2 with Ref. 1 and 2, it can be seen that, thanks to a transparent conductive coating and a low TL functional coating, comprising an absorbing layer, a laminated glazing is obtained having a light transmission within the target of 30 to 40%, a low interior and exterior reflection, respectively 13 and 15%, and improved selectivity compared to Ref. 2 that has the same TL.

[0247] The invention is not restricted to the use of functional coatings with two silver layers.