GLAZING PROVIDED WITH A THIN-LAYER STACK FOR SOLAR PROTECTION

Abstract

A solar protection and/or thermal insulation glazing including a substrate, in particular a glass substrate, provided with a stack of thin layers which act on solar radiation, the stack having the succession of the following layers, starting from the surface of the glass: an underlayer or a set of underlayers, the underlayer(s) having dielectric materials, a layer based on titanium oxide also having silicon, the overall Si/Ti atomic ratio in said layer being between 0.01 and 0.25, and in which Si and Ti represent at least 90% of the atoms other than oxygen, the thickness of the layer being between 20 and 70 nm, an overlayer or a set of overlayers, said overlayer(s) having dielectric materials.

Claims

1. A solar protection glazing comprising a substrate, preferably a glass substrate, provided with a stack of thin layers which act on solar radiation, in which said stack consists of the succession of the following layers, starting from the surface of the glass: an underlayer or a set of underlayers, said underlayer(s) consisting of dielectric materials, a layer based on titanium oxide also comprising silicon, the overall Si/Ti atomic ratio in said layer being between 0.01 and 0.25, and in which Si and Ti represent at least 90% of the atoms other than oxygen, the thickness of said layer being between 20 and 70 nm, an overlayer or a set of overlayers, said overlayer(s) consisting of dielectric materials.

2. The glazing as claimed in claim 1, wherein the dielectric materials constituting the overlayers and the underlayers are chosen from zinc oxides, silicon oxides, tin oxides, titanium oxides, zinc tin oxides, silicon and/or aluminum nitrides, and silicon and/or aluminum oxynitrides.

3. The glazing as claimed in claim 1, wherein the overall optical thickness of the underlayer(s) is between 30 and 90 nm.

4. The glazing as claimed in claim 1, wherein the overall optical thickness of the overlayer(s) is between 7 and 30 nm.

5. The glazing as claimed in claim 1, comprising, between the surface of the glass and the layer of titanium oxide, two underlayers, including one layer based on silicon oxide and one layer based on silicon nitride.

6. The glazing as claimed in claim 1, comprising, between the surface of the glass and the layer of titanium oxide, a single underlayer based on silicon nitride.

7. The glazing as claimed in claim 1, comprising, on top of the layer of titanium oxide, the succession of an overlayer based on silicon oxide and of an overlayer based on titanium oxide.

8. The glazing as claimed in claim 1, wherein the Si/Ti ratio is homogeneous throughout the thickness of the layer based on titanium oxide.

9. The glazing as claimed in claim 1, wherein the layer based on titanium oxide comprises a succession of strata in which the Si/Ti ratio ranges between 0 and 0.20.

10. The glazing as claimed in claim 1, wherein the overall Si/Ti atomic ratio in the layer is between 0.05 and 0.20, preferably is between 0.05 and 0.15.

11. The glazing as claimed in claim 1, wherein the light transmission T.sub.L is between 50% and 80% and preferably between 60% and 70%, and has a solar factor SF around the value of T.sub.L.

12. The glazing as claimed in claim 1, wherein it has undergone a heat treatment of the bending, tempering and/or annealing type.

13. A spandrel glazing as claimed in claim 1, which is at least partially, and preferably totally, opacified with an additional coating, said coating being in the form of an enamel or of a lacquer.

14. The spandrel glazing as claimed in claim 1, wherein the additional coating in the form of enamel or lacquer is deposited on top of the stack of layers.

15. A multiple glazing, in particular double glazing, incorporating a glazing or a panel as claimed in claim 1.

Description

EXAMPLE 1

[0056] In this comparative example and in accordance with the teaching of prior application WO 2007/028913, a stack consisting of an underlayer of silicon nitride, a layer of titanium oxide TiO.sub.x and two overlayers of SiO.sub.2 and of TiO.sub.x is deposited on the glass substrate according to the following sequence: [0057] Glass/SiN.sub.x (30 nm)/TiO.sub.x (22 nm)/SiO.sub.2 (7 nm)/TiO.sub.x (1 nm)

[0058] In this comparative example, the titanium oxide layer is deposited using a metallic target consisting only of titanium.

Example 2

[0059] In this example according to the invention, a stack similar to that described according to example 1 is deposited on the same substrate, but the TiO.sub.x layer is replaced with a TiO.sub.x-based layer, also comprising silicon. The layer is deposited using a metallic target comprising an alloy of titanium and silicon in an atomic proportion of 90/10. The thicknesses of the various constituent layers of the stack are also adjusted according to the techniques of the art so that the energy performance of the glazing thus obtained is identical to that of the glazing according to preceding example 1.

[0060] The stack deposited corresponds to the following sequence: [0061] Glass/SiN.sub.x (23 nm)/Ti.sub.0.9Si.sub.0.1O.sub.x (31 nm)/SiO.sub.2 (7 nm)/TiO.sub.x (1 nm)
It was verified by X-ray spectroscopy (EPMA microprobe) that the atomic proportions of titanium and silicon in the titanium oxide-based layer deposited in this way correspond substantially to those initially present in the metallic target, the Si/Ti atomic ratio measured being approximately 0.1.

EXAMPLE 3

[0062] In this comparative example, a stack of the same nature as that described according to example 1 is deposited on the same substrate, but the TiO.sub.x layer is replaced with a TiO.sub.x-based layer, also comprising zirconium. The layer is deposited using a metallic target comprising an alloy of titanium and zirconium in an atomic proportion of 90/10. The thicknesses of the various constituent layers of the stack are also adjusted according to the techniques of the art so that the energy performance of the glazing thus obtained is identical to that of the glazing according to preceding example 1.

The stack deposited therefore corresponds to the following sequence: [0063] Glass.sub.xSiN.sub.x (25 nm)/Ti.sub.0.9Zr.sub.0.1O.sub.x (30 nm)/SiO.sub.2 (7 nm)/TiO.sub.x (1 nm)
The optical properties and the colorimetry of the various glazings thus obtained according to examples 1 to 3 are measured according to the following criteria: [0064] transmission T.sub.L: light transmission as % according to illuminant D.sub.65, [0065] light reflection glass side: (RL.sub.v) as %, [0066] a*(R.sub.v), b*(R.sub.v): colorimetric coordinates in external reflection according to the L*, a*, b* colorimetry system, [0067] light reflection layer side: (RL.sub.c) as %, [0068] a*(R.sub.c), b*(R.sub.c): colorimetric coordinates in external reflection according to the L*, a*, b* colorimetry system, [0069] energy transmission: solar factor SF as % which measures the ratio of the total energy entering the premises to the incident solar energy.

TABLE-US-00001 TABLE 1 REFLECTION REFLECTION ENERGY LAYER GLASS SIDE TRANSMISSION TRANSMISSION SIDE (interior) (exterior) (Solar Factor) EXAMPLE T.sub.L a* b RL.sub.c L* a*.sub.(Rc) b*.sub.(Rc) RL.sub.V L* a* .sub.(Rv) b*.sub.(Rv) SF (%) Example 66 0.0 2.4 31 63 1.8 3.8 30 61 2.8 3.6 68 1 Example 67 0.0 2.3 31 63 2.0 3.2 30 61 3.1 2.7 68 2 Example 67 0.1 1.8 31 63 2.0 2.8 30 61 3.0 2.6 68 3

[0070] The results reported in table 1 show that the optical, colorimetric and energy performance levels of the three examples are substantially similar.

[0071] The above stacks are then subjected to the same heat treatment as that indicated in previous application WO 2007/028913, consisting of heating at 620 C. for 10 minutes, followed by tempering.

[0072] E* is defined in the following way:

E*=(L*.sup.2+a*.sup.2+b*.sup.2).sup.1/2, with L*, a* and b* the difference in the measurements of L*, a* and b* before and after the heat treatment.

[0073] The E* before and after heat treatment is about or close to 1% and all the glazings retain their sun protection property unchanged, as measured by the SF factor. They are also perfectly calibrated from an esthetic point of view, most particularly in external reflection, where the values of a* and b* are close to zero or slightly negative, giving a very neutral or slightly blue-green color which is accepted for glazings with high external reflection. All the values measured change very weakly under the influence of the heat treatment: the T.sub.L and SF values are preserved to within approximately 1%, the colorimetric data change very little, and there is no swing from one tint to another tint in external reflection. No optical defect of microcrack or pinhole type is observed on the three glazings.

[0074] The resistance of the stacks to heat treatments at higher temperature is then measured according to the following experimental protocol.

[0075] Lamellae of the same glazings as previously described according to examples 1 to 3 are firstly covered with a strip of enamel on top of the thin-layer stack, deposited by screen printing and consolidated by drying at 160 C.

[0076] The lamellae are then subjected to heat treatment in a gradient furnace comprising 3 different resistance zones. The settings of the 3 zones are initially adjusted in such a way that the temperature to which the lamellae are subjected ranges from one extremity to the other between 580 and 680 C.

The gradient is measured at the moment the glass exits the gradient furnace using a pyrometer which records 14 measurement points on the enamel.

[0077] After cooling, it is verified that none of the samples exhibits any optical defect of the microcrack or hole (pinhole) type. The surface of the stacks on the three samples thus appears to be even, uniform and defect-free.

[0078] The measurement of the L*, a*, b* parameters in reflection is carried out in a second step through the glass on the side of the non-covered face (i.e. glass side). The measurement is carried out using a Minolta CM-600d commercial spectrocolorimeter in D65 mode (illuminant D65). Such a measurement appears to be representative of the observation of a glazing from the exterior.

[0079] In addition, it constitutes an indirect measurement of the haze generated at the surface of the glazing, viewed from the exterior. In particular, since the layer of black enamel is a layer which absorbs light directly transmitted through the glazing, the parameter L* measured in reflection by the spectrocolorimeter at the surface of the lamella (glass side) is directly proportional to the scattering of the light generated at the level of the thin-layer stack. In other words, the greater the light fraction scattered by the glazing (in particular by the stack of layers), the greater the value of the parameter L* measured on the glass side.

[0080] The tests carried out by the applicant company showed that a measured value of L* of about 10 or more appears to be perceptible to the naked eye. In particular, above this critical haze value, the glazing loses its transparency and has an undesirable milky (translucent) appearance, all the more so the higher the L*.

[0081] The various L* values thus measured have been reported on the appended FIG. 1, as a function of the temperature gradient to which the various samples were subjected. Significant differences in the haze can be observed as a function of the nature of the titanium oxide-based layer present in the stack, and in particular of the critical heating temperature above which the glazing provided with its stack has an L* value which is too high, i.e. typically greater than 10: this temperature is 610 C. for the glazing comprising the TiO.sub.x layer only, 640 C. for the glazing comprising the Ti.sub.0.9Zr.sub.0.1O.sub.x layer, and 675 C. for the glazing comprising the Ti.sub.0.9Si.sub.0.1O.sub.x layer.

[0082] Most particularly, the data reported on the graph of FIG. 1 demonstrate that only the glazing comprising the Ti.sub.0.9Si.sub.0.1O.sub.x layer in the solar control stack can undergo a heat treatment of about 650 C., in particular required in a process for depositing a black enamel at the surface of the glazing. In conclusion, the solar protection glazings according to the invention are very advantageous for fitting buildings, without excluding applications in the automobile industry and any vehicles: side windows, rear window, sunroof, which can, moreover, have enameled coatings. With a stack of layers which is fixed, in particular according to the T.sub.L and energy transmission (SF) values that are desired, it is thus possible, without having to modify it, to manufacture vision glazings which are not intended to undergo heat treatments or which must be bent/tempered/annealed, and to manufacture spandrel panels in good colorimetric harmony with the vision glazings, which may be lacquered or enameled: it is thus possible to standardize the manufacture of interference layers on substrates of large size, which is a great advantage from the industrial point of view.