Material comprising a single functional layer containing silver and an absorbent layer

Abstract

A material includes a transparent substrate coated with a stack of thin layers I including a lower coating including at least one absorbent layer, a single silver-based functional metal layer and an upper coating including at least one dielectric layer. The absorbent layer is separated from the substrate and from the functional layer by one or more dielectric layers. The material, once fitted in a double glazing, makes it possible to obtain a high selectivity, in particular of greater than 1.45, an interior and exterior light reflection of less than 25% and bluish hues in exterior reflection and in interior reflection.

Claims

1. A material comprising a transparent substrate coated with a stack of thin layers comprising, starting from the substrate: a lower coating comprising: at least one dielectric layer, at least one absorbent layer, which absorbs solar radiation in the visible part of the spectrum, exhibiting a thickness of between 0.2 and 9 nm, at least one dielectric layer, a single silver-based functional metal layer, optionally a blocking layer, an upper coating comprising at least one dielectric layer, optionally a protective layer, wherein: the at least one absorbent layer is separated from the substrate and from the silver-based functional layer by one or more dielectric layers, a thickness of all the dielectric layers interposed between the at least one absorbent layer and the silver-based functional metal layer is between 3 and 18 nm and 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 1.45, an interior and exterior light reflection of less than 25%, a value of b* in exterior reflection of less than −5, a value of b* in interior reflection of less than −5.

2. The material as claimed in claim 1, wherein the thickness of all the dielectric layers interposed between the at least one absorbent layer and the substrate is greater than 11 nm.

3. The material as claimed in claim 1, wherein the at least one absorbent layer is chosen from: metal layers based on a metal or on a metal alloy, metal nitride layers and metal oxynitride layers, of one or more elements chosen from palladium, niobium, tungsten, stainless steel, titanium, chromium, molybdenum, zirconium, nickel, tantalum or zinc.

4. The material as claimed in claim 1, wherein the lower coating comprises a dielectric layer based on zinc oxide located directly in contact with the silver-based metal layer.

5. The material as claimed in claim 1, wherein the lower coating comprises a high-index layer based on metal oxide exhibiting a refractive index of greater than 2.20 and a thickness of greater than 5 nm.

6. The material as claimed in claim 5, wherein the high-index layer based on metal oxide are chosen from titanium oxide or niobium oxide layers or layers of an alloy obtained from titanium and niobium.

7. The material as claimed in claim 1, wherein the lower coating comprises at least the sequence of layers deposited in the following order: at least one layer having a high refractive index, made of material with a refractive index of greater than or equal to 2.20, a physical thickness of the layer having a high refractive index or the sum of the physical thicknesses of the layers having a high refractive index being between 10 and 40 nm, at least one absorbent layer, at least one zinc oxide layer.

8. The material as claimed in claim 1, wherein the upper coating comprises at least one high-index layer based on metal oxide exhibiting a refractive index of greater than 2.20 and a thickness of greater than 5 nm.

9. The material as claimed in claim 1, wherein the upper coating comprises at least the sequence of thin layers deposited in the following order above the functional layer: at least one blocking layer, at least one layer based on zinc oxide, at least one layer having a high refractive index, made of material with a refractive index of greater than or equal to 2.20, a physical thickness of the layer having a high refractive index or the sum of the physical thicknesses of the layers having a high refractive index being between 10 and 40 nm, at least one dielectric layer exhibiting a refractive index of less than 2.20 and a thickness of greater than 5 nm located above the high-index layer.

10. The material as claimed in claim 1, wherein the substrate is made of glass or of a polymeric organic substance.

11. The material as claimed in claim 10, wherein the glass is a soda-lime-silica glass.

12. A multiple glazing comprising at least one material as claimed in claim 1 and at least one second substrate, the material and the second substrate are separated by at least one inserted gas-filled cavity.

13. The multiple glazing as claimed in claim 12, wherein the glazing is a double glazing exhibiting, with the stack positioned on face 2: a selectivity of greater than 1.45, an interior and exterior light reflection of less than 25%, a value of b* in exterior reflection b*Rext of less than −5, a value of b* in interior reflection b*Rint of less than −5.

14. The glazing as claimed in claim 12, wherein the glazing exhibits an interior and exterior light reflection of less than 24%.

15. The glazing as claimed in claim 12, wherein the glazing exhibits: a neutral color in transmission with a b*T of less than 6, a blue color in reflection with a b*Rext and a bRint of less than −6 and optionally an a*Rext and an a*Rint of less than 5.

Description

(1) These figures respectively represent:

(2) FIG. 2: the variations in the values of b*T and b*Rext as a function of the position of the absorbent layer in the typical stack,

(3) FIG. 3: the variations in the values of a*T and a*Rext as a function of the position of the absorbent layer in the typical stack.

(4) In FIG. 2, the following are found: on the abscissa: the different positions P1 to P5 (defined above) of the absorbent layer in the typical stack, on the left-hand ordinate: the b*T values, on the right-hand ordinate: the b*Rext values.

(5) In FIG. 3, the following are found: on the abscissa: the different positions P1 to P5 (defined above) of the absorbent layer in the typical stack, on the ordinate: the a* values.

(6) The dotted lines “b*Rext ref”, “b*T ref”, “a*Rext ref” and “a*T ref” respectively represent the b*Rext, b*T, a*Rext and a*T values of the typical (or reference) stack not comprising an absorbent layer.

(7) The b*T, b*Rext, a*T and a*Rext curves respectively represent the b*T, b*Rext, a*T and a*Rext values as a function of the position of the absorbent layer in the stack.

(8) The following observations may be made.

(9) For the colors in reflection, whatever the position of the absorbent layer, its introduction results in a shift in the colors toward the yellow.

(10) This is because, in FIG. 2, all the b*Rext values are greater than the b*Rext value of the typical stack (b*Rext ref). However, when the absorbent layer is placed at the claimed position (P2), this shift is less pronounced and makes it possible to remain with b*Rext values below −6.

(11) The shift toward the yellow is much greater when the absorbent layer is placed in direct contact with the substrate and minimal when the absorbent layer is placed in direct contact with the silver layer.

(12) FIG. 3 shows that the color in reflection expressed by the a* values is strongly impacted and varies significantly with the position of the absorbent layer. When the absorbent layer is placed in the P1, P2 or P3 positions, an advantageous shift toward the green is observed.

(13) To place the absorbent layer at the claimed position makes it possible to clearly obtain a pair of a* and b* values in external reflection conferring a bluish hue.

(14) For the colors in transmission, the introduction of the absorbent layer at the claimed position: does not result in a significant shift in the colors on the yellow-blue axis (FIG. 2), results in a slight shift toward the green in the colors on the red-green axis (FIG. 3).

(15) It emerges from the pair a*T and b*T that an absence of shift toward the yellow and a shift toward the green are observed in transmission. To place the absorbent layer at the claimed position makes it possible to clearly obtain a pair of a* and b* values in transmission conferring a non-yellow, indeed even more neutral, hue.

(16) III.3. Impact of the Position of the Absorbent Layer on the Interior and Exterior Reflection

(17) The influence of the position of the absorbent layer on the variation in the interior and exterior light reflection is illustrated by FIG. 4.

(18) In FIG. 4, the following are found: on the abscissa: the different positions P1 to P5 (defined above) of the absorbent layer in the typical stack, on the ordinate: the light reflection values in %.

(19) The dotted lines “Rext ref” and “Rint ref” respectively represent the Rext and Rint values of the typical (or reference) stack not comprising an absorbent layer.

(20) The “Rext” and “Rint” curves respectively represent the Rext and Rint values as a function of the position of the absorbent layer in the stack.

(21) To place the absorbent layer at the claimed position makes it possible to obtain both an interior and exterior reflection of less than 22%.

(22) IV. “Solar Control” and Colorimetry Performance Qualities

(23) 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 positions with regard to the substrate carrying the stack (final line at the bottom of the table).

(24) TABLE-US-00003 TABLE 2 Comp. 1 Inv. 1 Inv. 2 Inv. 3 Inv. 4 Protective layer: TiO.sub.2 1 1 1 1 0.5 Coating Si.sub.3N.sub.4 16.5 15.9 13.1 14.4 12 SnZnO — — — — 10 TiO.sub.2 20 20 20 20 — TiO.sub.2—TiZrO — — — — 17 ZnO 5 5 5 5 6 Blocking layer Ti 0.3 0.3 0.3 0.3 0.2 NiCr — — — — — Functional Ag layer 18.6 17.7 17.2 16.9 16.8 Coating ZnO 5 5 5 5 5 Si.sub.3N.sub.4 — — — 5 — NiCr — 1.9 — 1.2 0.5 TiN — — 2.7 — — Si.sub.3N.sub.4 — — — 5 — TiO.sub.2 23 18.9 12.5 12.6 17.7 NiCr 1.2 — — — — Glass substrate (mm) 4 4 4 4 4

(25) Table 3 below lists the main optical characteristics measured when the materials form part of a double glazing of structure: 4-16-4 (Ar—90%). The stack is positioned on face 2, the face 1 of the glazing being the outermost face of the glazing, as usual.

(26) TABLE-US-00004 TABLE 3 Double glazing structure 4-16-4 (Ar-90%) fitted with the stack on face 2 Target value Comp. 1 Inv. 1 Inv. 2 Inv. 3 Inv. 4 LT % ≈60-70% 60.3 60.2 67.5 64.8 67.2 LRext % <25  14.4 19 19.2 17.1 23.5 LRint % <25  — — — — 21.4 SF <45  40.1 40 44.1 41.5 44.0 S   >1.5  1.503 1.505 1.53 1.56 1.53 a*T <0 −4.4 −5.2 −4.4 −4.9 −3.3 b*T <6 4.4 4.2 4.8 5 5.6 a*Rext <3 0.4 0.3 2.4 1.6 0.1 b*Rext <−6   −4.2 −7.9 −8.4 −10.3 −5.2 a*Rint <3 — — — — 2.4 b*Rint <−6   — — — — −9.6 SF: solar factor; S: the selectivity; -: not determined.?

(27) The comparative example Comp. 1 does not make it possible to obtain the bluish appearance desired. This is because, as explained above, the presence of the absorbent layer close to the substrate significantly absorbs the short visible wavelengths corresponding to the blue.

(28) The examples according to the invention make it possible: to retain the properties desired in terms of selectivity (S>1.5) and of exterior and interior reflection (<25%) and to obtain the esthetic appearance desired with in particular neutral colors in transmission but especially the bluish appearance in exterior and interior reflection which is expressed by b*Rext values of markedly less than −6.