Laminated glazing with coloured reflection and high solar transmittance, and solar energy systems employing the same

1. A laminated glazing unit for architectural integration of solar energy systems, comprising:

a layered glazing structure that includes

a substrate having a substrate refractive index n sub a value of which at a wavelength of 550 nm is between 1.45 and 1.6;

a multi-layered interference filter disposed on a first surface of the substrate and containing a non-quarter-wave thin-film stack defined at said wavelength of 550 nm,

wherein thicknesses of any two high-index material layers sandwiching an immediately-adjacent low-index material layer therebetween are different from one another and wherein thicknesses of any two low-index material layers sandwiching an immediately-adjacent high-index material layer therebetween are different from one another,

wherein the high-index layers each have a refractive index from 1.8 to 2.5 and the low refractive index layers each have a refractive index from 1.25 to 2.2;

and

a laminating polymer layer disposed on the multi-layered interference filter, said laminating polymer layer having a polymer refractive index n pol a value of which at the wavelength of 550 nm between 1.45 and 1.6;

wherein said layered glazing structure, when the substrate is in contact with an incident medium having a refractive index of n inc =1, is characterized by a first reflectance value for IR light at every wavelength between 1 micron and 2.5 micron is between 65% and 29% for at least angles of reflection of zero degrees, 65 degrees, 70 degrees, 75 degrees, 80 degrees, and 85 degrees.

2. The glazing unit according to claim 1 , wherein a second surface of the substrate contains a surface micro-structure or a surface nano-structure configured as a light diffuser for light at wavelengths in the visible portion the optical spectrum.

3. The glazing unit according to claim 1 , wherein at least one of the following conditions is satisfied:

(a) a variation of a dominant wavelength λ MD of a dominant color, characterizing said light in the visible portion of the optical spectrum that is reflected by the layered glazing structure at an angle θ r , of less than 5 nm for every θ r <60°; and

(b) the glazing unit further comprises a solar thermal collector or a solar photovoltaic (PV) panel disposed to be separated from the multi-layered interference filter by the laminating polymer layer.

4. The glazing unit according to claim 3 , wherein said solar thermal collector and said laminating polymer layer are in direct contact with one another.

5. The glazing unit according to claim 3 , wherein an active element of the solar PV panel is fully integrated in the layered glazing structure.

6. The glazing unit according to claim 1 , wherein the substrate comprises solar roll glass, an extra-white float glass with iron content of less than 120 ppm, or a polymeric material characterized by a total hemispherical solar transmittance higher than 90%.

7. The glazing unit according to claim 1 ,

wherein the laminating polymer layer comprises an elastomer cross-linking polymer, a thermoplastic product, or an ionoplastic polymer, and

wherein the total hemispherical solar transmittance of the glazing unit is higher than 92% when a thickness of the laminating polymer layer is between 0.4 mm and 0.5 mm.

8. The glazing unit according to claim 1 ,

wherein said multi-layered interference filter includes a thin-film stack of up to 9 layers that have corresponding physical thicknesses of up to 400 nm, wherein materials of said layers have corresponding extinction coefficients k not exceeding 0.2 at every wavelength between 450 nm and 2,500 nm.

9. The glazing unit according to claim 1 ,

wherein the substrate includes glass or polymer,

wherein said multi-layered interference filter is a spatially-asymmetric filter that includes 7 thin-film layers such that the layered glazing structure is configured to satisfy a design of:

incident medium of air|the substrate |H1|L1|H2|L2|H3|L3|H4| exit medium of said polymer layer,

wherein H1 denotes a layer of a high-refractive-index material with a refractive index of 1.8≤n H1 ≤2.5 at the wavelength of 550 nm and a first physical thickness of 100 nm±5%,

wherein L1 denotes a layer of a low-refractive-index material with a refractive index of 1.25≤n L1 ≤2.2 at the wavelength of 550 nm and a second physical thickness of 57 nm±5%,

wherein H2 denotes a layer of the high-refractive-index material with the refractive index of 1.8≤n H2 ≤2.5 at the wavelength of 550 nm and a third physical thickness of 29 nm±10%, and

wherein L2 denotes a layer of the low-refractive-index material with a refractive index of 1.25≤n L2 ≤2.2 at the wavelength of 550 nm and a fourth physical thickness of 37 nm±10%,

wherein H3 denotes a layer of the high-refractive-index material with the refractive index of 1.8≤n H3 ≤2.5 at the wavelength of 550 nm and a fifth physical thickness of 39 nm±10%,

wherein L3 denotes a layer of the low-refractive-index material with a refractive index of 1.25≤n L3 ≤2.2 at the wavelength of 550 nm and a sixth physical thickness of 45 nm±10%,

wherein H4 denotes a layer of the high-refractive-index material with the refractive index of 1.8n H4 ≤2.5 at the wavelength of 550 nm and a seventh physical thickness of 15 nm±15%,

and

wherein light incident onto the substrate and reflected by said article is perceived as yellow or greenish-yellow.

10. The glazing unit according to claim 1 ,

wherein the substrate includes glass or polymer,

wherein said multi-layered interference filter is a spatially-asymmetric filter that includes 5 thin-film layers such that the layered glazing structure is configured to satisfy a design of:

incident medium of air the substrate |H1|L1|H2|L2|H3| exit medium of said polymer layer,

wherein H1 denotes a layer of a high-refractive-index material with a refractive index of 1.8≤n H1 ≤2.5 at the wavelength of 550 nm and a first physical thickness of 97 nm±5%,

wherein L1 denotes a layer of a low-refractive-index material with a refractive index of 1.25≤n L1 ≤2.2 at the wavelength of 550 nm and a second physical thickness of 120 nm±2.5%,

wherein H2 denotes a layer of the high-refractive-index material with the refractive index of 1.8≤n H2 ≤2.5 at the wavelength of 550 nm and a third physical thickness of 48 nm±10%, and

wherein L2 denotes a layer of the low-refractive-index material with a refractive index of 1.25≤n L2 ≤2.2: at the wavelength of 550 nm and a fourth physical thickness of 17 nm±15%,

wherein H3 denotes a layer of the high-refractive-index material with the refractive index of 1.8≤n H3 ≤2.5 at the wavelength of 550 nm and a fifth physical thickness of 113 nm±2.5%,

and

wherein light incident onto the substrate and reflected by said article is perceived as yellowish-green.

11. The glazing unit according to claim 1 ,

wherein the substrate includes glass or polymer,

wherein said multi-layered interference filter is a spatially-asymmetric filter that includes 5 thin-film layers such that the layered glazing structure is configured to satisfy a design of:

incident medium of air|the substrate |H1|L1|H2|L2|H3| exit medium of said polymer layer,

wherein H1 denotes a layer of a high-refractive-index material with a refractive index of 1.8≤n H1 ≤2.5 at the wavelength of 550 nm and a first physical thickness of 70 nm±5%,

wherein L1 denotes a layer of a low-refractive-index material with a refractive index of 1.25≤n L1 ≤2.2 at the wavelength of 550 nm and a second physical thickness of 70 nm±5%,

wherein H2 denotes a layer of the high-refractive-index material with the refractive index of 1.8≤n H2 ≤2.5 at the wavelength of 550 nm and a third physical thickness of 50 nm+10%, and

wherein L2 denotes a layer of the low-refractive-index material with a refractive index of 1.25≤n L2 ≤2.2 at the wavelength of 550 nm and a fourth physical thickness of 50 nm±10%,

wherein H3 denotes a layer of the high-refractive-index material with the refractive index of 1.8≤n H3 ≤2.5 at the wavelength of 550 nm and a fifth physical thickness of 20 nm±15%,

and

wherein light incident onto the substrate and reflected by said article is perceived as yellowish-green.

12. The glazing unit according to claim 1 ,

wherein the substrate includes glass or polymer,

wherein said multi-layered interference filter is a spatially-asymmetric filter that includes 9 thin-film layers such that the layered glazing structure is configured to satisfy a design of:

incident medium of air the substrate |H1|L1|H2|L2|H3|L3|H4|L4|H5| exit medium of said polymer layer,

wherein said multi-layered interference filter is a spatially-asymmetric filter that includes 9 thin-film layers such that the layered glazing structure is configured to satisfy a design of:

incident medium of air the substrate |H1|L1|H2|L2|H3|L3|H4|L4|H5| exit medium of said polymer layer,

wherein H1 denotes a layer of a high-refractive-index material with a refractive index of 1.8≤n H1 ≤2.5 at the wavelength of 550 nm and a first physical thickness of 20 nm±15%,

wherein L1 denotes a layer of a low-refractive-index material with a refractive index of 125≤n L1 ≤2.2 at the wavelength of 550 nm and a second physical thickness of 44 nm±10%,

wherein H2 denotes a layer of the high-refractive-index material with the refractive index of 1.8≤n H2 ≤2.5 at the wavelength of 550 nm and a third physical thickness of 36 nm±10%,

wherein L2 denotes a layer of the low-refractive-index material with a refractive index of 1.25≤n L2 ≤2.2 at the wavelength of 550 nm and a fourth physical thickness of 155 nm±2.5%,

wherein H3 denotes a layer of the high-refractive-index material with the refractive index of 1.8n H3 ≤2.5 at the wavelength of 550 nm and a fifth physical thickness of 20 nm±15%,

wherein L3 denotes a layer of the low-refractive-index material with a refractive index of 1.25≤n L2 ≤2.2 at the wavelength of 550 nm and a fourth physical thickness of 175 nm±2.5%,

wherein H4 denotes a layer of the high-refractive-index material with the refractive index of 1.8≤n H3 ≤2.5 at the wavelength of 550 nm and a fifth physical thickness of 74 nm±5%,

wherein L4 denotes a layer of the low-refractive-index material with a refractive index of 1.25≤n L2 ≤2.2 at the wavelength of 550 nm and a fourth physical thickness of 183 nm±2.5%,

wherein H5 denotes a layer of the high-refractive-index material with the refractive index of 1.8≤n H5 ≤2.5 at the wavelength of 550 nm and a fifth physical thickness of 109 nm±2.5%,

and

wherein light incident onto the substrate and reflected by said unit is perceived as greenish-blue.

13. The glazing unit according to claim 1 , wherein at least one of the following conditions is satisfied:

(a) wherein a value of saturation of color, of light incident onto the substrate and reflected by said glazing unit and defined by C ab *=√{square root over ((α*) 2 +(b*) 2 )} according to CIE color coordinates L*, a* and b* under daylight illumination CIE-D65, is higher than 8 at normal angle of reflection; and

(b) a total hemispherical solar transmittance is above 80% at normal incidence.

14. A laminated glazing unit for architectural integration of solar energy systems, comprising:

a layered glazing structure that includes

a substrate having a substrate refractive index n sub a value of which at a wavelength of 550 nm is between 1.45 and 1.6;

a multi-layered interference filter disposed on a first surface of the substrate and containing a non-quarter-wave thin-film stack defined at said wavelength of 550 nm,

wherein thicknesses of any two high-index material layers sandwiching an immediately-adjacent low-index material layer therebetween are different from one another and wherein thicknesses of any two low-index material layers sandwiching an immediately-adjacent high-index material layer therebetween are different from one another,

wherein the high-index layers each have a refractive index from 1.8 to 2.5 and the low refractive index layers each have a refractive index from 1.25 to 2.2;

and

a laminating polymer layer disposed on the multi-layered interference filter, said laminating polymer layer having a polymer refractive index n pol a value of which at the wavelength of 550 nm between 1.45 and 1.6;

wherein said layered glazing structure, when the substrate is in contact with an incident medium having a refractive index of n inc =1, is characterized by a first reflectance value for IR light at every wavelength between 1 micron and 2.5 micron is between 65% and 14% for at least angles of reflection of zero degrees, 65 degrees, 70 degrees, 75 degrees, 80 degrees, and 85 degrees.

15. The glazing unit according to claim 14 , wherein a variation of a dominant wavelength λ MD of a dominant color, characterizing said light in the visible portion of the optical spectrum that is reflected by the layered glazing structure at an angle θ r , is less than at least one of

a) 3 nm for every θ r <60°; and

b) 1 nm for every θ r <75°.

16. The glazing unit according to claim 14 , characterized by a total hemispherical solar transmittance value that is above 80% at normal incidence.

17. The glazing unit according to claim 14 , further comprising a solar thermal collector or a solar photovoltaic (PV) panel disposed to be separated from the multi-layered interference filter by the laminating polymer layer.

18. A laminated glazing unit for architectural integration of solar energy systems, comprising:

a layered glazing structure that includes a substrate having a substrate refractive index n sub a value of which at a wavelength of 550 nm is between 1.45 and 1.6;

a multi-layered interference filter disposed on a first surface of the substrate and containing a non-quarter-wave thin-film stack defined at said wavelength of 550 nm,

wherein thicknesses of any two high-index material layers sandwiching an immediately-adjacent low-index material layer therebetween are different from one another and wherein thicknesses of any two low-index material layers sandwiching an immediately-adjacent high-index material layer therebetween are different from one another,

wherein the high-index layers each have a refractive index from 1.8 to 2.5 and the low refractive index layers each have a refractive index from 1.25 to 2.2;

and

a laminating polymer layer disposed on the multi-layered interference filter, said laminating polymer layer having a polymer refractive index n pol a value of which at the wavelength of 550 nm between 1.45 and 1.6;

wherein said layered glazing structure, when the substrate is in contact with an incident medium having a refractive index of n inc =1, is characterized by a first reflectance value for IR light at every wavelength between 1 micron and 2.5 micron is between 18% and 5% for at least angles of reflection of zero degrees, 15 degrees, 30 degrees, 45 degrees, 60 degrees, 70 degrees, and 75 degrees.

19. The glazing unit according to claim 18 , characterized by a total hemispherical solar transmittance value that is above 90% at normal incidence.

20. The glazing unit according to claim 18 , further comprising a solar thermal collector or a solar photovoltaic (PV) panel disposed to be separated from the multi-layered interference filter by the laminating polymer layer.