Material provided with a stack having thermal properties

Abstract

A material includes a transparent substrate coated with a stack of thin layers including an alternation of three functional silver-based metallic layers. This material makes it possible to obtain a multiple glazing having good thermal performance results, in particular a selectivity greater than 2, excellent color neutrality and low optical sensitivity.

Claims

1. A material comprising a transparent substrate coated with a stack of layers successively comprising, from the substrate, an alternation of three functional silver-based metallic layers referred to as, starting from the substrate, first, second and third functional metallic layers, thicknesses of the first, second and third functional metallic layers, starting from the substrate, increasing as a function of the distance from the substrate, and of four dielectric coatings referred to as, starting from the substrate, first dielectric coating M1, second dielectric coating M2, third dielectric coating M3 and fourth dielectric coating M4 which each have an optical thickness Eo1, Eo2, Eo3 and Eo4, respectively, each dielectric coating comprising at least one dielectric layer, in such a way that each functional metallic layer is placed between two dielectric coatings; each metallic layer can be placed above or below a blocking layer, or both, the stack comprising at least one blocking layer located in contact with a functional metallic layer, wherein: a ratio of the thickness of the second functional metallic layer to the thickness of the first functional metallic layer Ag2/Ag1 is greater than or equal to 1.05, a ratio of the thickness of the third functional metallic layer to the thickness of the second functional metallic layer Ag3/Ag2 is greater than or equal to 1.05, the first and second dielectric coatings M1 and M2 each have a total optical thickness of between 50 and 130 nm, a ratio of the total optical thicknesses of the first dielectric coating M1 to the second dielectric coating M2 is between 0.80 and 1.15 including these values, the thickness of each blocking layer is between 0.1 and 1.8 nm and a sum of thicknesses of all of the blocking layers is between 0.3 and 3.5 nm.

2. The material as claimed in claim 1, wherein the ratio of the optical thicknesses of the fourth dielectric coating M4 to the first dielectric coating M1 is less than or equal to 0.95.

3. The material as claimed in claim 2, wherein the ratio of the optical thicknesses of the fourth dielectric coating to the first dielectric coating is less than 0.85.

4. The material as claimed in claim 1, wherein the optical thickness Eo4 of the fourth dielectric coating M4 is from 50 to 120 nm.

5. The material as claimed in claim 4, wherein the optical thickness Eo4 of the fourth dielectric coating M4 is from 70 to 90 nm.

6. The material as claimed claim 1, wherein the three functional metallic layers satisfy the following characteristics: the ratio of the thickness of the second functional metallic layer to the thickness of the first functional metallic layer Ag2/Ag1 is between 1.05 and 2.30, including these values, and/or the ratio of the thickness of the third functional metallic layer to the thickness of the second functional metallic layer Ag3/Ag2 is between 1.05 and 1.50, including these values, the ratio of the thickness of the third functional metallic layer to the thickness of the first functional metallic layer Ag3/Ag1 is between 1.15 and 2.50, including these values.

7. The material as claimed in claim 1, wherein one or more of the blocking layers are deposited above the functional layers and a total thickness of all the blocking layers above the functional layers is between 0.5 and 3.5 nm including these values.

8. The material as claimed in claim 1, wherein the stack comprises, starting from the substrate: the first dielectric coating comprising at least one dielectric layer having a barrier function and one dielectric layer having a stabilizing function, optionally a blocking layer, the first functional metallic layer, optionally a blocking layer, the second dielectric coating comprising at least one lower dielectric layer having a stabilizing function, one dielectric layer having a barrier function and one upper dielectric layer having a stabilizing function, optionally a blocking layer, the second functional metallic layer, optionally a blocking layer, the third dielectric coating comprising at least one lower dielectric layer having a stabilizing function, one dielectric layer having a barrier function and one upper dielectric layer having a stabilizing function, optionally a blocking layer, the third functional metallic layer, a blocking layer, the fourth dielectric coating comprising at least one dielectric layer having a stabilizing function, one dielectric layer having a barrier function and optionally a protective layer.

9. The material as claimed in claim 1, wherein, when the material is fitted in a double glazing with the stack positioned on face 2, the double glazing exhibits: a selectivity of greater than 1.08, an internal and external light reflection of less than 20%, a light transmission of between 40 and 70%.

10. The material as claimed in claim 1, wherein, when the material is fitted in a double glazing with the stack positioned on face 2, the double glazing has the colorimetric characteristics in external reflection, in internal reflection or in transmission defined by: values of a* of between −5 and +5; values of b* of between −5 and +5.

11. The material as claimed in claim 10, wherein the values of a* is between −3 and +3, and the values of b* is between −3 and +3.

12. The material as claimed in claim 1, wherein the stack has values of optical sensitivity in external reflection ΔCi of less than 5 for all layers making up the stack having a thickness greater than equal to 10 nm.

13. The material as claimed in claim 3, wherein the first and second dielectric coatings M1 and M2 each have an optical thickness Eo1 and Eo2 from 70 to 130 nm.

14. The material as claimed in claim 1, wherein the stack has a value of optical sensitivity in external reflection ΔCi of less than 4 for each layer making up the stack having a thickness from 10 nm to 100 nm.

15. A glazing comprising at least one material as claimed in claim 1, wherein the glazing is in the form of monolithic, laminated or multiple glazing.

16. The glazing as claimed in claim 12, comprising the material and at least one second substrate, the material and the second substrate being separated by at least one inserted gas-filled cavity.

17. The multiple glazing as claimed in claim 15, wherein the glazing is a double glazing exhibiting, with the stack positioned on face 2: a selectivity of greater than 1.8, an internal and external light reflection of less than 20%, a light transmission of between 40 and 70%, values of a* in external reflection comprised between −5 and +5, values of b* in external reflection comprised between −5 and +5.

18. The multiple glazing as claimed in claim 15, wherein each layer of the stack having a thickness of greater than equal to 10 nm has an optical sensitivity ΔCi in external reflection of less than 5.

19. The glazing as claimed in claim 15, wherein the glazing is a double glazing or triple glazing.

Description

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

(2) FIG. 1 illustrates a stack structure comprising three functional metallic 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:

(3) 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.

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

(5) 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.

(6) 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.

(7) Each dielectric coating 20, 60, 100, 140 comprises a dielectric layer having a barrier function based on silicon nitride, doped with aluminum, referred to here as Si.sub.3N.sub.4 24, 64, 104, 144, or based on mixed zinc tin oxide 106.

(8) The stack can also comprise: blocking underlayers 30, 70 and 110 (not represented) 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

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

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

(10) In the examples of the invention: the functional layers are silver (Ag) layers, the blocking layers are metallic layers made of alloy of nickel and of chromium (NiCr), the barrier layers are based on silicon nitride, doped with aluminum (Si.sub.3N.sub.4:Al) or based on mixed zinc tin oxide (SnZnO.sub.x), the stabilizing layers are made of zinc oxide (ZnO).

(11) The conditions for deposition of the layers, which were deposited by sputtering (“magnetron cathode” sputtering), are summarized in table 1.

(12) TABLE-US-00001 TABLE 1 Deposition Target employed pressure Gas n 550 nm Si.sub.3N.sub.4 Si:Al at 92:8% by weight 3.2 × 10.sup.−3 mbar 55% Ar/(Ar + N.sub.2) 2.18 ZnO Zn:Al at 98:2% by weight 1.8 × 10.sup.−3 mbar 63% Ar/(Ar + O.sub.2) 1.91 SnZnO.sub.x Sn:Zn (60:40% by weight) 1.5 × 10.sup.−3 mbar 39% Ar—61% O.sub.2 2.12 TiZrO TiZrO.sub.x 2.4 × 10.sup.−3 mbar 90% Ar—10% O.sub.2 2.32 NiCr Ni (80 at. %):Cr (20 at. %) 2-3 × 10.sup.−3 mbar 100% Ar — Ag Ag .sup. 3 × 10.sup.−3 mbar 100% Ar — At. = atomic

(13) Table 2 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.

(14) TABLE-US-00002 TABLE 2 Ref. Inv. 1 Inv. 2 Comp. 3 Comp. 4 DC: M4 140 37.7 40.4 39.6 58 Si.sub.3N.sub.4 144 29.7 32.4 31.6 50 ZnO 142 8 8 8 8 BL: NiCr 130 0.3 0.5 0.55 1 FL: Ag3 120 15 15.8 13 10 BL: NiCr 110 0 0 0 0 DC: M3 100 79.8 86.4 78 98 ZnO 108 8 8 8 8 SnZnO 106 12 12 8 8 Si.sub.3N.sub.4 104 51.8 54.4 54 74 ZnO 102 8 8 8 8 BL: NiCr 90 0.2 0.3 0.6 0.4 FL: Ag2 80 12.3 14.9 10.8 11.8 BL: NiCr 70 0.1 0.1 0.1 0.1 DC: M2 60 49.9 61 48 68.5 ZnO 68 8 8 8 8 Si.sub.3N.sub.4 64 33.9 45 32 52.5 ZnO 62 8 8 8 8 BL: NiCr 50 0.3 1.1 1 1.9 FL: Ag1 40 11.3 7.5 7 10 BL: NiCr 30 0.3 0.6 0.5 0.5 DC: M1 20 45.3 54.8 67.5 43 ZnO 28 8 8 8 8 Si.sub.3N.sub.4 24 37.3 46.8 59.5 35 Substrate (mm) 10 6 6 6 6 DC: Dielectric coating; BL: Blocking layer; FL: Functional layer.

(15) The characteristics related to the thicknesses of the functional layers and of the dielectric coatings are summarized in table 3 below.

(16) TABLE-US-00003 TABLE 3 Inv. 1 Inv. 2 Comp. 3 Comp. 4 DC Ep Eo Ep Eo Ep Eo Ep Eo M1 45.3 96.6 54.8 117.3 67.5 145 43 91.5 M2 49.9 104.5 61 128.7 48 100.3 68.5 145 M3 79.8 169.6 86.4 175.3 78 165.7 98 209.3 M4 37.7 80 40.4 85.9 39.6 84 58 124.2 M2/M1 (Eo) 1.08 1.1  0.69 1.58 M1 ≈ M2 M1 ≈ M2 M1 > M2 M1 < M2 M4/M1 (Eo) 0.83 0.73 0.58 1.36 M1 > M4 M1 > M4 M1 > M4 M1 < M4 Ag2/Ag1 1.08 1.99 1.54 1.18 Ag3/Ag2 1.21 1.06 1.20 0.85 Ag3/Ag1 1.32 2.10 1.85 1   Σ Ep BL 1.2  2.90 2.75 3.9  DC: Dielectric coating; BL: Blocking layer; Ep: Physical thickness; Eo: Optical thickness.

II. “Solar Control” and Colorimetry Performance Qualities

(17) The main optical characteristics measured when the glazings are part of a double glazing with a 6/16/4 structure: 6-mm glass/16-mm interlayer space filled with 90% of argon and 10% of air/4-mm glass 4 mm, the stack being positioned on face 2 (face 1 of the glazing being the outermost face of the glazing), are listed in table 4

(18) TABLE-US-00004 TABLE 4 Target value Inv. 1 Inv. 2 Comp. 3 Comp. 4 “g” % ≤30%  28 28 26.8 25 “s” >2.0 2.1 2.1 1.73 1.8 LT % 50-60%.sup.  56 56 46.6 44 a*T −4 < a* < 4 −3 −3 −6 0 b*T −4 < b* < 4 −1 −1 −2.5 0 LRext % <20% 15 15 18.8 16.5 a*Rext −4 < a* < 4 −2 −2 −0.2 −2 b*Rext −4 < b* < 4 −2 −2 −6.5 −5 LRint % <20% 18 18 18.8 20 a*Rint −4 < a* < 4 −2 −2 −3 −7 b*Rint −4 < b* < 4 −2 −2 −3 −15

(19) The glazings according to the invention simultaneously exhibit a solar factor of less than or equal to 30% and a selectivity of greater than 2.0. These glazings additionally exhibit an external and internal reflection at least less than 20%.

(20) However, above all, these glazings are neutral in internal and external reflection and in transmission. Indeed, the values of a* and b* are all between −4 and 4, or even between −3 and 3.

(21) For comparative example 3, the value of a* in transmission and the value of b* in external reflection are less than −4. In addition, for this example, the selectivity is too low.

(22) For comparative example 4, the value of a* in internal reflection and the value of b* in external and internal reflection are less than −4. In addition, for this example, the selectivity is too low.

(23) The proposed solution therefore makes it possible to have a solar factor of less than 30% while keeping a selectivity greater than 2.0 and an extremely neutral esthetic.

III. Determination of the Optical Sensitivity in External Reflection

(24) The table below summarizes the values of optical sensitivity in external reflection of each layer of the stacks having a geometric thickness of greater than 10 nm.

(25) TABLE-US-00005 TABLE 5 ΔCi Ref. Inv. 1 Inv. 2 Comp. 3 Comp. 4 M4: Si.sub.3N.sub.4 144 3.7 3.3 4.2 1.1 FL: Ag3 120 2.7 2 2.3 0.5 M3: SnZnO 106 0.5 0.7 — M3: Si.sub.3N.sub.4 104 3.8 1.8 2.3 5 FL: Ag2 80 2.2 1.9 1.5 3 M2: Si.sub.3N.sub.4 64 0.8 1.0 0.5 7 FL: Ag1 40 2.2 1.1 0.2 3 M1: Si.sub.3N.sub.4 24 2.2 2.1 4 2

(26) According to the invention, a low optical sensitivity in external reflection of a stack comprising i layers results in ΔCi values of less than 5, preferably less than 4, and better still less than 3, for all the i layers making up the stack having a thickness greater than equal to 10 nm.

(27) For the examples according to the invention all the ΔCi values are less than 4 and most are less than 3.

(28) Comparative example 3 is not satisfactory because two ΔCi values are greater than or equal to 4. Added to this is the fact that the selectivity of this example is too low.

(29) Comparative example 4 is not satisfactory because two ΔCi values are greater than or equal to 4, one of them being equal to 7. Added to this is the fact that the selectivity of this example is too low.

(30) The proposed solution therefore makes it possible to simultaneously have high selectivity, excellent color neutrality and low optical sensitivity.