Material provided with a stack having thermal properties

Abstract

A material includes a transparent substrate coated with a stack of thin layers successively including, starting from the substrate, an alternation of three silver-based functional metal layers of increasing thickness and of four dielectric coatings denoted, starting from the substrate, M1, M2, M3 and M4, wherein each dielectric coating includes at least one high-index dielectric layer, the refractive index of which is at least 2.15 and the optical thickness of which is greater than 20 nm.

Claims

1. A material comprising a transparent substrate coated with a stack of layers successively comprising, starting from the substrate, an alternation of three silver-based functional metal layers denoted, starting from the substrate, first, second and third functional layers, the thicknesses of the functional metal layers, starting from the substrate, increase as a function of the distance from the substrate, and of four dielectric coatings denoted, starting from the substrate, a first dielectric coating M1, a second dielectric coating M2, a third dielectric coating M3 and a fourth dielectric coating M4, each dielectric coating comprising at least one dielectric layer, so that each functional metal layer is positioned between two dielectric coatings, wherein: the first, second, third and fourth dielectric coatings M1, M2, M3 and M4 each have an optical thickness To1, To2, To3 and To4, respectively, each dielectric coating comprises at least one high-index dielectric layer, the refractive index of which is at least 2.15 and the optical thickness of which is greater than 20 nm, a sum of the optical thicknesses of all the high-index dielectric layers of one and the same dielectric coating is denoted, according to the dielectric coating concerned, Tohi1, Tohi2, Tohi3 or Tohi4, each dielectric coating satisfies the following relationship: Tohi1/To1>0.30, Tohi2/To2>0.30, Tohi3/To3>0.30, Tohi4/To4>0.30, wherein the three silver-based functional metal layers satisfy the following characteristics: a ratio of the thickness of the second functional metal layer to the thickness of the first functional metal layer is between 1.20 and 2.00, including these values, and/or a ratio of the thickness of the third functional metal layer to the thickness of the second functional metal layer is between 1.20 and 1.80, including these values.

2. The material as claimed in claim 1, wherein the stack additionally comprises at least one blocking layer located in contact with one of the functional metal layers, which at least one blocking layer is chosen from metal layers, metal nitride layers, metal oxide layers and metal oxynitride layers of one or more elements chosen from titanium, nickel, chromium and niobium.

3. The material as claimed in claim 1, wherein the first, second, third and fourth dielectric coatings M1, M2, M3 and M4 each have an optical thickness To1, To2, To3 and To4 satisfying the following relationship: To4<To1<To2<To3.

4. The material as claimed in claim 1, wherein the high-index dielectric layers exhibit a refractive index of less than or equal to 2.35.

5. The material as claimed in claim 1, wherein each dielectric coating satisfies the following relationship: Tohi1/To1>0.80, Tohi2/To2>0.80, Tohi3/To3>0.80, Tohi4/To4>0.80.

6. The material as claimed in claim 1, wherein at least two dielectric coatings comprise a high-index dielectric layer based on zirconium silicon nitride.

7. The material as claimed in claim 1, wherein each dielectric coating comprises a high-index dielectric layer based on zirconium silicon nitride.

8. The material as claimed in claim 1, wherein the dielectric coatings satisfy the following characteristics: the optical thickness of the first dielectric coating M1 is from 60 to 140 nm, the optical thickness of the second dielectric coating M2 is from 120 to 180 nm, the optical thickness of the third dielectric coating M3 is from 140 to 200 nm, the optical thickness of the fourth dielectric coating M4 is from 50 to 120 nm.

9. The material as claimed in claim 1, wherein each dielectric coating additionally comprises at least one dielectric layer, a refractive index of which is less than 2.15.

10. The material as claimed in claim 1, wherein the stack, defined starting from the transparent substrate, comprises: the first dielectric coating M1 comprising at least one high-index dielectric layer, optionally a layer having a barrier function, a dielectric layer having a stabilizing function, optionally a blocking layer, the first functional layer, optionally a blocking layer, the second dielectric coating M2 comprising at least one lower dielectric layer having a stabilizing function, optionally a layer having a barrier function, a high-index dielectric layer, optionally a layer having a smoothing function, an upper dielectric layer having a stabilizing function, optionally a blocking layer, the second functional layer, optionally a blocking layer, the third dielectric coating M3 comprising at least one lower dielectric layer having a stabilizing function, optionally a layer having a barrier function, a high-index dielectric layer, optionally a layer having a smoothing function, an upper dielectric layer having a stabilizing function, optionally a blocking layer, the third functional layer, optionally a blocking layer, the fourth dielectric coating M4 comprising at least one dielectric layer having a stabilizing function, optionally a layer having a barrier function, a high-index dielectric layer and optionally a protective layer.

11. A process for obtaining a material as claimed in claim 1, comprising depositing the layers of the stack by magnetron cathode sputtering.

12. A glazing comprising at least one material as claimed in claim 1.

13. The glazing as claimed in claim 12, wherein the stack is positioned in the glazing so that an incident light originating from the outside passes through the first dielectric coating before passing through the first functional metal layer.

14. The glazing as claimed in claim 12, wherein the glazing is in the form of a multiple glazing.

15. The glazing as claimed in claim 2, wherein the at least one blocking layer is selected from the group consisting of Ti, TiN, TiO.sub.2, Nb, NbN, Ni, NiN, Cr, CrN, NiCr or NiCrN layer.

16. The glazing as claimed 15, wherein the glazing is in the form of a double glazing or a triple glazing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 illustrates a stack structure comprising three functional metal layers according to an embodiment of the invention, and

(2) FIG. 2 represents the variation of light transmission TL as a function of the solar factor for different examples.

(3) The proportions between the various components are not observed in order to make the figures easier to read.

(4) FIG. 1 illustrates a stack structure comprising three functional metal layers 40, 80, 120, this structure being deposited on a transparent glass substrate 10. Each functional layer 40, 80, 120 is positioned between two dielectric coatings 20, 60, 100, 140 so that: the first functional layer 40 starting from the substrate is positioned between the dielectric coatings 20, 60, the second functional layer 80 is positioned between the dielectric coatings 60, 100 and the third functional layer 120 is positioned between the dielectric coatings 100, 140.

(5) These dielectric coatings 20, 60, 100, 140 each comprise at least one dielectric layer 24, 25, 26, 28; 62, 63, 64, 66, 68; 102, 103, 104, 106, 108; 142, 144.

(6) The stack can also comprise: blocking underlayers 30, 70 and 110 (not represented), 50, 90 and 130 located in contact with a functional layer, blocking overlayers 50, 90 and 130 located in contact with a functional layer, a protective layer (not represented).

EXAMPLES

(7) I. Preparation of the Substrates: Stacks, Deposition Conditions and Heat Treatments

(8) Stacks of thin layers defined below are deposited on substrates made of clear soda-lime glass with a thickness of 6 mm.

(9) The materials according to the invention and the comparative materials have colors which satisfy the criteria defined in the colorbox reference below. The optical characteristics are measured: on materials in the form of a double glazing of 6/16/4 structure: 6-mm glass/16-mm interlayer space filled with 90% argon/4-mm glass, the stack been positioned on face 2 (the face 1 of the glazing being the outermost face of the glazing, as usual), on materials in the form of a single glazing with a 6-mm substrate and the stack being positioned on face 2.

(10) TABLE-US-00001 TABLE 1 Colorbox reference Double glazing Single glazing a*T b*T Rext a*ext b*ext Rint a*int b*int a*g60 b*g60 5 2 12 3.5 5 13 3 3 4.5 3 2.0 1.5 1 1 1.2 3 3 2 2.2 2

(11) For the double glazings: a*T and b*T indicate the colors in transmission a* and b* in the L*a*b* system, measured according to the illuminant D65 at 2 Observer and measured perpendicularly to the glazing; Rext indicates: the light reflection in the visible region in %, measured according to the illuminant D65 at 2 Observer on the side of the outermost face, the face 1; a*Rext and b*Rext indicate the colors in reflection a* and b* in the L*a*b* system, measured according to the illuminant D65 at 2 Observer on the side of the outermost face and measured thus perpendicularly to the glazing; Rint indicates: the light reflection in the visible region in %, measured according to the illuminant D65 at 2 Observer on the side of the interior face, the face 4; a*Rint and b*Rint indicate the colors in reflection a* and b* in the L*a*b* system, measured according to the illuminant D65 at 2 Observer on the side of the interior face and measured thus perpendicularly to the glazing.

(12) The colorimetric values at an angle a*g60 and b*g60 are measured on a single glazing under an incidence of 60. This gives an account of the neutrality of the colors at an angle.

(13) In the examples of the invention: the functional layers are silver (Ag) layers, the blocking layers are titanium oxide layers, the high-index layers are chosen from layers based on zirconium silicon nitride and titanium oxide layers, the barrier layers are based on silicon nitride, doped with aluminum (Si.sub.3N.sub.4:Al), the stabilizing layers are made of zinc oxide (ZnO), the smoothing layers are based on a mixed oxide of zinc and tin (SnZnO.sub.x).

(14) The zirconium silicon nitride layers are deposited from a metal target comprising silicon, zirconium and aluminum.

(15) The conditions for deposition of the layers, which were deposited by sputtering (magnetron cathode sputtering), are summarized in table 2.

(16) TABLE-US-00002 TABLE 2 Target Deposition n 550 employed pressure Gas nm Si.sub.3N.sub.4 Si:Al at 92:8% 3.2 10.sup.3 mbar 55% Ar/ 2.06 by weight (Ar + N.sub.2) SiZrAlN Si:Al:Zr 3.2 10.sup.3 mbar 55% Ar/ 2.22 (70:8:22 at. %) (Ar + N.sub.2) ZnO Zn:Al at 98:2% 1.8 10.sup.3 mbar 63% Ar/ 1.95 by weight (Ar + O.sub.2) SnZnO.sub.x Sn:Zn 1.5 10.sup.3 mbar 39% Ar - 2.04 (60:40% by wt) 61% O.sub.2 TiO.sub.x TiO.sub.x 1.5 10.sup.3 mbar 88% Ar - 2.45 12% O.sub.2 NiCr Ni (80 at. %):Cr 2-3 10.sup.3 mbar 100% Ar (20 at. %) Ag Ag .sup.3 10.sup.3 mbar 100% Ar at. = atomic

(17) Table 3 lists the materials and the physical thicknesses in nanometers (unless otherwise indicated) of each layer or coating which forms the stacks as a function of their position with regard to the substrate carrying the stack (final line at the bottom of the table). The Ref numbers correspond to the references of FIG. 1.

(18) Each dielectric coating 20, 60, 100 below a functional layer 40, 80, 120 comprises a final stabilizing layer 28, 68, 108 based on crystalline zinc oxide, which is in contact with the functional layer 40, 80, 120 deposited immediately above.

(19) Each dielectric coating 60, 100, 140 above a functional layer 40, 80, 120 comprises a first stabilizing layer 62, 102, 142 based on crystalline zinc oxide, which is in contact with the functional layer 40, 80, 120 deposited immediately above.

(20) Each dielectric coating 20, 60, 100, 140 comprises a high-index dielectric layer 24, 64, 104, 144, based on zirconium silicon nitride or on titanium oxide.

(21) The dielectric coatings 20, 60, 100, 140 can comprise a dielectric layer having a barrier function 25, 63, 103, 143, based on silicon nitride doped with aluminum, known here as Si.sub.3N.sub.4.

(22) The dielectric coatings 20, 60, 100 can additionally comprise a smoothing layer based on a mixed oxide of zinc and tin 26, 66, 106.

(23) Each functional metal layer 40, 80, 120 is below and in contact with a blocking layer 50, 90 and 130.

(24) TABLE-US-00003 TABLE 3 Ref. Inv. 1 Inv. 2 Inv. 3 Comp. 1 Comp. 2 Comp. 3 Comp. 4 Dielectric coating M4 140 38.9 34.8 31.5 41.6 38.7 50.0 50.0 TiO.sub.x 144 0.0 0.0 23.5 0.0 0.0 0 0 SiZrN 144 14.6 29.8 0.0 0.0 14.4 40.0 40.0 Si.sub.3N.sub.4 143 16.3 0.0 0.0 33.6 16.3 0.0 0.0 ZnO 142 8.0 5.0 8.0 8.0 8.0 10.0 10.0 Blocking layer NiCr 130 0.5 0.5 0.5 0.5 0.5 0.1 0.1 Functional layer Ag3 120 17.7 18.0 17.6 17.7 16.5 16 18 Blocking layer NiCr 110 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Dielectric coating M3 100 79.1 74.4 76.8 78.6 81.0 85.0 85.0 ZnO 108 8.0 5.0 8.0 8.0 8.0 10.0 10.0 SnZnO 106 8.0 0.0 0.0 0.0 0.0 6.0 6.0 SiZrN 104 26.3 64.4 60.8 0.0 0.0 59.0 59.0 Si.sub.3N.sub.4 103 28.8 0.0 0.0 62.6 65.0 0.0 0.0 ZnO 102 8.0 5.0 8.0 8.0 8.0 10.0 10.0 Blocking layer TiO.sub.x 90 0.5 0.5 0.5 0.5 0.5 0.1 0.1 Functional layer Ag2 80 14.3 14.2 13.5 11.9 13.3 16 18 Blocking layer NiCr 70 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Dielectric coating M2 60 71.1 67.0 72.2 65.1 72.0 87.0 87.0 ZnO 68 8.0 5.0 8.0 8.0 8.0 10.0 10.0 SnZnO 66 8.0 0.0 0.0 0.0 0.0 6.0 6.0 SiZrN 64 21.4 57.0 56.2 0.0 0.0 63.0 63.0 Si.sub.3N.sub.4 63 25.7 0.0 0.0 49.1 56.0 0.0 0.0 ZnO 62 8.0 5.0 8.0 8.0 8.0 8.0 8.0 Blocking layer TiO.sub.x 50 0.5 0.5 0.5 0.5 0.5 0.1 0.1 Functional layer Ag1 40 9.6 9.5 8.8 11.0 11.1 15 18 Blocking layer NiCr 30 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Dielectric coating M1 20 44.4 43.1 39.3 31.8 44.4 44.0 44.0 ZnO 28 8.0 5.0 8.0 8.0 8.0 10.0 10.0 SnZnO 26 0.0 0.0 0.0 0.0 8.0 6.0 6.0 Si.sub.3N.sub.4 25 8.0 0.0 0.0 23.8 0.0 0.0 0.0 SiZrN 24 28.4 38.1 0.0 0.0 28.4 28.0 28.0 TiO.sub.x 24 0.0 0.0 31.3 0.0 0.0 0.0 0.0 Glass substrate (mm) 10 6.0 6.0 6.0 6.0 6.0 6.0 6.0

(25) The characteristics related to the thicknesses of the functional layers and of the dielectric coatings are summarized in table 4.

(26) TABLE-US-00004 TABLE 4 Inv. 1 Inv. 2 Inv. 3 Comp. 1 Comp. 2 Comp. 3 Comp. 4 DC Tp To Tp To Tp To Tp To Tp To Tp To Tp To M1 44.4 95.1 43.1 94.3 39.3 92.3 31.8 64.6 44.4 95.0 44.0 91.2 44.0 91.2 M2 71.1 148.0 67 146.0 72.2 156.0 65.1 132.3 72 146.6 87.0 181.7 87.0 181.7 M3 79.1 165.2 74.4 162.5 76.8 166.2 78.6 160.2 81 165.1 85.0 176.8 85.0 176.8 M4 38.9 81.1 34.8 75.9 31.5 73.2 41.6 83.8 38.7 80.7 50.0 105 50.0 105 Ag2/Ag1 1.49 1.49 1.53 1.08 1.20 1.07 1.00 Ag3/Ag2 1.24 1.27 1.30 1.49 1.24 1.00 1.00 Ag1 + Ag2 + Ag3 41.60 41.70 39.90 40.60 40.85 47 54 M1 Tohi1/To1 0.66 0.90 0.83 0.00 0.66 0.66 0.66 M2 Tohi2/To1 0.32 0.87 0.81 0.00 0.00 0.72 0.72 M3 Tohi3/To1 0.35 0.88 0.81 0.00 0.00 0.72 0.72 M4 Tohi4/To1 0.40 0.87 0.79 0.00 0.40 0.82 0.82 Tp BL 1.50 1.50 1.50 1.50 1.50 0.30 0.30 DC: Dielectric coating; BL: Blocking layer; Tp: Physical thickness; To: Optical thickness.
II. Solar Control Performance Results

(27) The energy performance results obtained when the glazings form parts of a double glazing as are described above are listed in table 5.

(28) TABLE-US-00005 TABLE 5 Target value Inv. 1 Inv. 2 Inv. 3 Comp. 1 Comp. 2 Comp. 3 Comp. 4 g % 34.0% 32.9 33.6 34.0 34.82 34.35 28.4 23.5 s >2.00 2.10 2.06 2.00 1.93 1.99 2.26 2.5 LT % 70% 69.0 69.3 68.1 67.06 68.4 64.4 58.9

(29) In the first embodiment (Inv.1), each dielectric coating M1 to M4 comprises a high-index layer based on zirconium silicon nitride.

(30) In the second embodiment (Inv.2), each dielectric coating M1 to M4 comprises a high-index layer based on zirconium silicon nitride and the ratio of the optical thickness of this high-index layer to the optical thickness of the dielectric coating containing it is greater than 0.5, preferably greater than 0.8. The best performance results are obtained for this example.

(31) In the third embodiment (Inv.3), the dielectric coatings M1 and M4 comprise high-index layers based on TiO.sub.2 and the dielectric coatings M2 and M3 comprise high-index layers based on zirconium silicon nitride. The performance results are less advantageous than when all the dielectric coatings are based on SiZrN but better than those obtained with for comparative examples 1 and 2.

(32) In comparative example 1, no dielectric coating M1 to M4 comprises a high-index layer with an optical thickness of greater than 20 nm.

(33) In comparative example 2, the dielectric coatings M1 and M4 do not comprise a high-index layer with an optical thickness of greater than 20 nm and the dielectric coatings M2 and M3 contain high-index layers based on zirconium silicon nitride. The performance results are poorer than those obtained for the materials of the invention, each dielectric coating of which comprises a high-index layer.

(34) The performance results obtained with the different examples are summarized in FIG. 2. A scatter of points is given in order to illustrate the range of performance results which are accessible, while retaining the colors in the reference colorbox, with the materials of type Inv.1 and Inv.2, that is to say materials comprising, in each dielectric coating, a high-index layer based on zirconium silicon nitride.

(35) According to the invention, it is possible to produce a glazing comprising a stack having three functional metal layers with exhibits a light transmission of approximately 70%, a high selectivity, a low light reflection and a low solar factor. The glazings according to the invention simultaneously exhibit a solar factor of less than or equal to 34% and a selectivity of greater than 2.00. These glazings additionally exhibit an external reflection at least less than 15%.

(36) The examples according to the invention all exhibit a pleasant and subdued coloration in transmission, preferably within the range of the blues or blue-greens.

(37) The solution provided thus makes it possible to achieve the following performance results: a light transmission of approximately 70%, a solar factor of approximately 33%, a low reflection on the external side, and a neutral esthetic quality.