GLAZING FOR SOLAR PROTECTION PROVIDED WITH THIN-FILM COATINGS

Abstract

A solar protection glazing includes a substrate covered with a coating of dielectric materials on each of its faces. The substrate is preferably a glass substrate. Each of the coatings consists of a layer based on titanium oxide or of a stack of layers of dielectric materials incorporating such a layer. The thickness of the layers based on titanium oxide in each of the coatings is between 10 and 70 nm.

Claims

1. A solar protection glazing comprising: a substrate, said substrate being covered with a coating of dielectric materials on each of us faces wherein each of the coatings consists of a layer based on titanium oxide or of a slack of layers of dielectric materials incorporating such a layer, the thickness of the layers based on titanium oxide being between 10 and 70 nm.

2. The solar protection glazing as claimed in claim 1, wherein said dielectric materials are chosen from the nitrides, oxides or oxynitrides,

3. The solar protection glazing as claimed in claim 1, wherein the dielectric materials, besides the layers based on titanium oxide, are chosen from zinc oxides, silicon oxides, tin oxides, zinc tin oxides, silicon and/or aluminum nitrides, and silicon and/or aluminum oxynitrides.

4. The solar protection glazing as claimed in claim 1, wherein at least one of said stacks consists of the succession of the following layers, starting from the surface of the substrate: an underlayer or a set of underlayers, said underlayer(s) consisting of dielectric materials, and a layer based on titanium oxide, the thickness of which is between 10 and 70 nm.

5. The solar protection glazing as claimed in claim 4, wherein at least one of said coatings consists of a single layer based on titanium oxide.

6. The solar protection glazing, as claimed in claim 1, further comprising, on a first face of the substrate, a first coating deposited by pyrolysis or by CVD and, on a second face of the substrate, a second coating, deposited by a vacuum deposition technique.

7. The solar protection glazing as claimed in claim 6, wherein the coating deposited by pyrolysis is a layer based on titanium oxide and wherein the coating deposited by a vacuum deposition technique is a stack of layers which consists of the succession of the following layers, starting from the surface of the substrate: an underlayer or a set of underlayers, said underlayer(s) consisting of dielectric materials, and a layer based on titanium oxide, the thickness of which is between 10 and 70 nm.

8. The solar protection glazing as claimed in claim 1, wherein at least one of the layers based on titanium oxide also comprises an element X chosen from silicon, zirconium, niobium and tantalum, the overall X/Ti atomic ratio in said layer being between 0.01 and 0.25, Ti and X representing at least 90% of the atoms other than oxygen.

9. The solar protection glazing as claimed in claim 8, wherein X is silicon.

10. The solar protection glazing as claimed in claim 1, wherein at least one of the layers based on titanium oxide essentially consists of titanium and oxygen.

11. The solar protection glazing as claimed in claim 10, wherein said layer(s) based on titanium oxide comprises) less than 1 mol % of elements other than titanium and oxygen.

12. The solar protection glazing as claimed in claim 1, wherein the thickness of the layers based on titanium oxide in each stack is between 20 and 60 nanometers.

13. The solar protection glazing as claimed in claim 1, wherein a light reflection on each of the faces of the glazing is greater than 30%.

14. The solar protection glazing as claimed in claim 1, wherein a solar factor is less than 60%.

15. The solar protection glazing as claimed in claim 1, wherein a light transmission is between 45% and 60%.

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

17. A spandrel glazing, comprising: the solar protection glazing as claimed claim 1, which is at least partially opacified with an additional coating, said coating being in the form of an enamel or of a lacquer.

18. The spandrel glazing as claimed in claim 17, wherein the additional coating in the form of enamel or lacquer is deposited on top of the stack of layers.

19. A multiple glazing, comprising: the glazing as claimed in claim 1.

20. The solar protection glazing as claimed in claim 1, wherein said substrate is a glass substrate.

Description

EXAMPLE 1

Prior Art

[0074] In this example obtained in accordance with the teaching of application WO 2007/028913, a stack consisting of an underlayer of silicon nitride, of a layer of titanium oxide TiO.sub.x and of an overlayer of SiO.sub.2 is deposited on one face of the glass substrate by the magnetron sputtering techniques as previously described.

[0075] The glazing provided with its stack is represented schematically by the following sequence:

Glass/SiN.sub.x (23 nm)/TiO.sub.x(30 nm)/SiO.sub.2 (7 nm)

EXAMPLE 2

Comparative

[0076] In this comparative example, a stack of the same nature as that described according to example 1 is deposited on the same substrate with the only difference being that the device is regulated so that the layer of TiO.sub.x is twice as thick (60 nm),

The glazing provided with its stack is represented schematically by the following sequence:

Glass/SiN.sub.x (23 nm)/TiO.sub.x (60 nm)/SiO.sub.2 (7 nm)

EXAMPLE 3

Comparative

[0077] In this comparative example, a stack of the same nature as that described according to example 1 is deposited on the same substrate with the only difference being that the layer of TiO.sub.x deposited is even thicker, so as to reach a thickness equal to 70 nm.

[0078] The glazing provided with its stack is represented schematically by the following sequence:

Glass/SiN.sub.x (23 nm)/TiO.sub.x (70 nm)/SiO.sub.2 (7 nm)

EXAMPLE 4

According to the Invention

[0079] In this example according to the invention, a stack similar to that described according to example 1 is deposited on a glass substrate of the same type by the vacuum sputtering techniques, The other face is this time provided with a pyrolytic coating of titanium oxide, deposited beforehand on the ribbon of hot glass exiting the float bath, according to the techniques which are standard in the field.

[0080] The glazing provided with the two coatings on each of its faces is represented schematically by the following sequence:

TiO.sub.2 pyro (30 nm)/Glass/SiN.sub.x (23 nm)/TiO.sub.x (30 nm)/SiO.sub.2 (7 nm)

[0081] With reference to example 1, according to examples 2 and 3, an overthickness of TiO.sub.2 is deposited within the stack of layers for the purpose of improving the anti-sun performances of the glazing, Alternatively, according to example 4 according to the invention, this same additional amount of TiO.sub.2 is added to the glazing of example 1, but on the other face of the glazing and not within the stack.

[0082] The optical properties and the colorimetry of the various glazings thus obtained according to examples 1 to 4 are measured according to the following criteria in accordance with standard NF EN410 (2011): [0083] transmission T.sub.L: light transmission as % according to illuminant D.sub.65, [0084] light reflection glass side: (RL.sub.v) as %, [0085] a*(R.sub.v), b*(R.sub.v): colorimetric coordinates in external reflection according to the L, a*, b* colorimetry system, [0086] light reflection layer side: (RL.sub.c) as [0087] a*(R.sub.c), b*(R.sub.c): colorimetric coordinates in external reflection according to the L*, a*, b* colorimetry system, [0088] 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 LAYER GLASS SIDE SOLAR TRANSMISSION SIDE (interior) (exterior) FACTOR EXAMPLE T.sub.L a* b* RL.sub.c a*.sub.(Rc) b*.sub.(Rc) RL.sub.V a*.sub.(Rv) b*.sub.(Rv) SF (%) Example 1 66 0 3 31 2 3 30 3 3 65 (prior art) Example 2 70 1 8 27 1 21 26 1 21 67 (comparative) Example 3 76 4 5 21 7 18 20 6 18 68 (comparative) Example 4 53 0 3 44 2 6 44 3 6 58 (the invention)

[0089] The results reported in table 1 indicate the light and energy performances of the glazings according to the three examples.

[0090] Comparison of examples 1 to 3 shows that the increase in thickness of the layer of titanium oxide within a stack present on a single face of the glass substrate does not bring about any improvement in the thermal insulation properties of the glazing, as indicated by the solar factor values reported in table 1.

[0091] Conversely, the depositing of a layer of titanium oxide corresponding to the thickness of the layer according to example 2, but this time on the other face of the glass substrate (example 4 according to the invention) this time brings about a significant improvement in the energy insulation properties of the glazing, while at the same time preserving a light transmission greater than 50%.

[0092] 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 air-tempering.

[0093] The colorimetry variation E* is defined in the following ay. 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.

[0094] The E* before and after heat treatment is about or close to 1% and all the glazings retain their anti-sun 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, 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.

EXAMPLES 5 to 10

According to the Invention

[0095] In these examples, single layers of titanium oxide are deposited, as coating, on each of the faces of the glass substrate Planiluxt, by vacuum sputtering techniques. For each example, various thicknesses are deposited, as reported in table 2 which follows.

[0096] The glazing provided with the two layers of titanium oxide is represented schematically by the following sequence:

TiO.sub.x (x.sub.1 nm)/Glass/TiO.sub.x (x.sub.2 nm)

[0097] The light and energy characteristics of the various glazings obtained are measured as previously indicated and reported in the following table 2:

TABLE-US-00002 TABLE 2 THICKNESS THICKNESS ENERGY TiO.sub.2 layer TiO.sub.2 layer TRANSMISSION first face second face TRANSMISSION (Solar Factor) EXAMPLE (x.sub.1) (x.sub.2) T.sub.L a* b* SF (%) Example 5 55 10 58 1 1 62 (the invention) Example 6 55 20 54 1 3 59 (the invention) Example 7 55 30 50 1 5 56 (the invention) Example 8 55 40 47 1 4 54 (the invention) Example 9 55 55 45 2 0 52 (the invention) Example 10 55 70 47 2 6 53 (the invention)

[0098] The results reported in table 2 show that the solar factor can be brought to much lower values by application of the present invention and can be in particular lowered by 13% (in absolute value) compared with the best performance observed according to the prior art configurations (previous example 1), which appears to be entirely significant for the desired application. Thus, in any event, the energy performances noted for the glazings according to the invention are greater than that which can be obtained according to the teaching of application WO 2007/028913, the light transmission remaining at an acceptable level for use in particular in the construction industry or else as side windows.