Laminated glazing with coloured reflection and high solar transmittance suitable for solar energy systems

Abstract

A laminated and etched glazing unit having a substrate and a multi-layered interference filter each delimited by two main faces; the incident medium having a refractive index n.sub.inc=1, the substrate having a refractive index n.sub.substrate defined as: 1.45n.sub.substrate1.6 at 550 nm, and the exit medium being defined as follows 1.45n.sub.exit1.6 at 550 nm; and wherein the following requirements are met: The saturation of the colour is higher than 8 at near-normal angle of reflection, except for grey and brown; the visible reflectance is higher than 4%; the variation of the dominant wavelength .sub.MD of the dominant colour M.sub.D of the reflection is smaller than 15 nm for .sub.r<60; and the total hemispherical solar transmittance is above 80%.

Claims

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.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 1.4 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.sub.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.sub.inc=1, is characterized by: a) a first reflectance value for IR light at every wavelength between 1 micron and 2.5 micron that is between 65% and 17% for at least angles of reflection of zero degrees,65 degrees, 70 degrees, 75 degrees, 80 degrees, and 85 degrees; and b) a value of saturation of color, given by C*.sub.ab={square root over ((a*).sup.2+(b*).sup.2)} according to CIE color coordinates L*, a* and b* under daylight illumination CIE-D65 that is higher than 8 at normal angle of reflection, except for grey and brown; and c) a second reflectance value R.sub.vis for light in a visible portion of an optical spectrum at near-normal incidence that is higher than 4%; and d) a variation of a dominant wavelength .sub.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 .sub.r, of less than 15 nm for every .sub.r<60; and e) a total hemispherical solar transmittance above 80% at normal incidence.

2. The glazing unit according to claim 1, the first reflectance value for IR light at every wavelength between 1 micron and 2.5 micron is between 20% and 13.2% for at least the angles of reflection of said IR light of zero degrees, 60 degrees, and 65 degrees.

3. 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.

4. The glazing unit according to claim 1, wherein the layered glazing structure includes an anti-reflection (AR) coating at a backside of the laminated glazing structure, said AR coating configured to ensure that a solar transmittance for light that has passed through the substrate, the multi-layered interference filter, and through the laminating polymer layer to interact with exposed surface is increased by about 3% after said AR coating is disposed.

5. The glazing 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 solar transmittance higher than 90%.

6. 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 further comprising a pane of glass or polymer material laminated with said layered glazing structure via said laminating polymer layer, wherein the total hemispherical solar transmittance of the article is higher than 92% when a thickness of the laminating polymer layer is between 0.4 mm and 0.5 mm.

7. 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.

8. The glazing unit according to claim 1, wherein the substrate includes glass or polymer, wherein said multi-layered interference filter includes a spatially-asymmetric filter that includes 3 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| exit medium of said polymer layer, wherein H1 denotes a layer of a high-refractive-index material with a refractive index of 1.8n.sub.H12.5 at the wavelength of 550 nm and a first physical thickness of 3012 nm, wherein L1 denotes a layer of a low-refractive-index material with a refractive index of 1.4n.sub.L12.2 at the wavelength of 550 nm and a second physical thickness of 2512 nm, wherein H2 denotes a layer of the high-refractive-index material with the refractive index of 1.8n.sub.H22.5 at the wavelength of 550 nm and a third physical thickness of 32012 nm, and wherein light incident onto the substrate and reflected by said glazing unit is perceived as green.

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 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 1.8n.sub.H12.5 at the wavelength of 550 nm and a first physical thickness of 18512 nm, wherein L1 denotes a layer of a low-refractive-index material with a refractive index of 1.4n.sub.L12.2 at the wavelength of 550 nm and a second physical thickness of 2512 nm, wherein H2 denotes a layer of the high-refractive-index material with the refractive index of 1.8n.sub.H22.5 at the wavelength of 550 nm and a third physical thickness of 3512 nm, and wherein L2 denotes a layer of the low-refractive-index material with a refractive index of 1.4n.sub.L22.2 at the wavelength of 550 nm and a fourth physical thickness of 3512 nm, wherein H3 denotes a layer of the high-refractive-index material with the refractive index of 1.8n.sub.H32.5 at the wavelength of 550 nm and a fifth physical thickness of 13012 nm, and wherein light incident onto the substrate and reflected by said glazing unit is perceived as green.

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 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 1.8n.sub.H12.5 at the wavelength of 550 nm and a first physical thickness of 16012 nm, wherein L1 denotes a layer of a low-refractive-index material with a refractive index of 1.4n.sub.L12.2 at the wavelength of 550 nm and a second physical thickness of 13012 nm, wherein H2 denotes a layer of the high-refractive-index material with the refractive index of 1.8n.sub.H22.5 at the wavelength of 550 nm and a third physical thickness of 6512 nm, and wherein L2 denotes a layer of the low-refractive-index material with a refractive index of 1.4n.sub.L22.2 at the wavelength of 550 nm and a fourth physical thickness of 2512 nm, wherein H3 denotes a layer of the high-refractive-index material with the refractive index of 1.8n.sub.H32.5 at the wavelength of 550 nm and a fifth physical thickness of 7012 nm, wherein L3 denotes a layer of the low-refractive-index material with a refractive index of 1.4n.sub.L32.2 at the wavelength of 550 nm and a fourth physical thickness of 16012 nm, wherein H4 denotes a layer of the high-refractive-index material with the refractive index of 1.8n.sub.H42.5 at the wavelength of 550 nm and a fifth physical thickness of 10012 nm, and wherein light incident onto the substrate and reflected by said glazing unit is perceived as green.

11. The glazing unit according to claim 1, wherein the substrate includes glass or polymer, wherein said multi-layered interference filter includes 3 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| exit medium of said polymer layer, wherein H1 denotes a layer of a high-refractive-index material with a refractive index of 1.8n.sub.H12.5 S at the wavelength of 550 nm and a first physical thickness of 4512 nm, wherein L denotes a layer of a low-refractive-index material with a refractive index of 1.4n.sub.L12.2 at the wavelength of 550 nm and a second physical thickness of 7012 nm, wherein H2 denotes a layer of the high-refractive-index material with the refractive index of 1.8n.sub.H22.5 at the wavelength of 550 nm and a third physical thickness of 4512 nm, and wherein light incident onto the substrate and reflected by said glazing unit is perceived as 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 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 1.8n.sub.H12.5 at the wavelength of 550 nm and a first physical thickness of 17512 nm, wherein L1 denotes a layer of a low-refractive-index material with a refractive index of 1.4n.sub.L12.2 at the wavelength of 550 nm and a second physical thickness of 8512 nm, wherein H2 denotes a layer of the high-refractive-index material with the refractive index of 1.8n.sub.H22.5 at the wavelength of 550 nm and a third physical thickness of 5012 nm, and wherein L2 denotes a layer of the low-refractive-index material with a refractive index of 1.4n.sub.L22.2 at the wavelength of 550 nm and a fourth physical thickness of 2512 nm, wherein H3 denotes a layer of the high-refractive-index material with the refractive index of 1.8n.sub.H32.5 at the wavelength of 550 nm and a fifth physical thickness of 30012 nm, and wherein light incident onto the substrate and reflected by said glazing unit is perceived as yellow-green.

13. 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 1.8n.sub.H12.5 at the wavelength of 550 nm and a first physical thickness of 12012 nm, wherein L1 denotes a layer of a low-refractive-index material with a refractive index of 1.4n.sub.L12.2 at the wavelength of 550 nm and a second physical thickness of 12012 nm, wherein H2 denotes a layer of the high-refractive-index material with the refractive index of 1.8n.sub.H22.5 at the wavelength of 550 nm and a third physical thickness of 9512 nm, and wherein L2 denotes a layer of the low-refractive-index material with a refractive index of 1.4n.sub.L22.2 at the wavelength of 550 nm and a fourth physical thickness of 9012 nm, wherein H3 denotes a layer of the high-refractive-index material with the refractive index of 1.8n.sub.H32.5 at the wavelength of 550 nm and a fifth physical thickness of 9012 nm, wherein L3 denotes a layer of the low-refractive-index material with a refractive index of 1.4n.sub.L32.2 at the wavelength of 550 nm and a fourth physical thickness of 9512 nm, wherein H4 denotes a layer of the high-refractive-index material with the refractive index of 1.8n.sub.H42.5 at the wavelength of 550 nm and a fifth physical thickness of 10012 nm, and wherein light incident onto the substrate and reflected by said glazing unit is perceived as yellow-orange.

14. The glazing unit according to claim 1, wherein the substrate includes glass or polymer, wherein said multi-layered interference filter includes 2 thin-film layers such that the layered glazing structure is configured to satisfy a design of incident medium of air the substrate |H1|L1 exit medium of said polymer layer, wherein H1 denotes a layer of a high-refractive-index material with a refractive index of 1.8n.sub.H12.5 at the wavelength of 550 nm and a first physical thickness of 4015 nm, wherein L1 denotes a layer of a low-refractive-index material with a refractive index of 1.4n.sub.L12.2 at the wavelength of 550 nm and a second physical thickness of 7530 nm, and wherein light incident onto the substrate and reflected by said glazing unit is perceived as gray.

15. The glazing unit article of manufacture according to claim 1, wherein the substrate includes glass or polymer, wherein said multi-layered interference filter is a spatially-asymmetric filter that includes 4 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| exit medium of said polymer layer, wherein H1 denotes a layer of a high-refractive-index material with a refractive index of 1.8n.sub.H12.5 at the wavelength of 550 nm and a first physical thickness of 5012 nm, wherein L1 denotes a layer of a low-refractive-index material with a refractive index of 1.4n.sub.L12.2 at the wavelength of 550 nm and a second physical thickness of 9012 nm, wherein H2 denotes a layer of a high-refractive-index material with a refractive index of 1.8n.sub.H22.5 at the wavelength of 550 nm and a first physical thickness of 6512 nm, wherein L2 denotes a layer of a low-refractive-index material with a refractive index of 1.4n.sub.L22.2 at the wavelength of 550 nm and a second physical thickness of 5512 nm, and wherein light incident onto the substrate and reflected by said glazing unit is perceived as brown.

16. The glazing unit according to claim 1, 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.

17. The glazing unit according to claim 16, wherein said solar thermal collector and said laminating polymer layer are in direct contact with one another.

18. The glazing unit according to claim 16, wherein an active element of the solar PV panel is fully integrated in the layered glazing structure.

Description

LIST OF FIGURE CAPTIONS

(1) FIG. 1:

(2) Angular dependency of 1931 CIE (x, y) colour coordinates under CIE-D65 illuminant of the coloured design given in Example 1.

(3) FIG. 2:

(4) Reflectance curves of the coating design given in Example 1 for various angles of reflection (from 0 to 85).

(5) FIGS. 3A, 3B, and 3C:

(6) Schematic drawings of possible configurations of coloured laminated glazing for thermal and PVT applications. The coloured coating can be deposited: FIG. 3Aon the back side of the outer glass, FIG. 3Bon one side of a polymeric film which is encapsulated between two glass panes, FIG. 3Con the front side of the inner glass.

(7) FIGS. 4A, 4B, and 4C:

(8) Schematic drawings of possible configurations of coloured laminated glazing for PV applications. The coloured coating can be deposited: FIG. 4Aon the back side of the outer glass, FIG. 4Bon one side of a polymeric film which is encapsulated between two glass panes, FIG. 4Con the front side of the inner glass. Here the technical parts of the PV device are fully integrated into the laminated glazing.

(9) FIG. 5:

(10) 1988 C.I.E. normalised photopic luminous efficiency function delimiting the part of the solar spectrum which is visible for the human eye and reflectance curve at normal incidence (angle of vision of 0) of a yellow-green coating (.sub.max=570 nm) presenting a single reflection peak.

(11) FIG. 6:

(12) 1988 C.I.E. normalised photopic luminous efficiency function delimiting the part of the solar spectrum which is visible for the human eye and reflectance curve at normal incidence (angle of vision of 0) of a green coating (.sub.D=500 nm) presenting three reflection peaks in the visible part of the solar spectrum (bulk part of the curve).

(13) FIGS. 7A, 7B: FIG. 7A: Reflectance curves of a yellow-green coating for various angles of reflection (from 0 to 85). The reflection peak situated in the visible part of the spectrum shifts to smaller wavelengths: .sub.max varies from .sub.max 0=570 nm to .sub.max 60=500 nm leading to a colour change of the coating from yellow-green to green. FIG. 7B: Same representation for a green coating design presenting three reflection peaks in the visible part of the solar spectrum.

(14) FIGS. 8A, 8B: FIG. 8A: Graphical representation of a fictive reflectance curve composed by two reflection peaks in the visible part of the solar spectrum. .sub.1, C.sub.1 and .sub.2, C.sub.2 are the wavelengths and colours of the reflectance peaks at low viewing angle. .sub.1, C.sub.1 and .sub.2, C.sub.2 are the corresponding wavelengths and colours at higher angle of observation. The dominant colour M.sub.D of the coating is situated at .sub.D comprised between .sub.1 and .sub.2, its position depending on the relative intensity of both reflection peaks. FIG. 8B: Principle of colour stability represented on the 1931 C.I.E. chromaticity diagram. M is the resultant colour of a coating characterised by 2 reflection peaks, in the visible part of the solar spectrum, defined by C.sub.1 and C.sub.2 at low angle of vision. C.sub.1 and C.sub.2 are the corresponding colours for higher angle of vision. M.sub.D is the dominant colour of M.

(15) FIGS. 9A, 9B: FIG. 9A: Graphical representation of a fictive reflectance curve composed by three reflection peaks in the visible part of the solar spectrum. .sub.1, C.sub.1, .sub.2, C.sub.2 and .sub.3, C.sub.3 are the wavelengths and colours of the reflectance peaks at low viewing angle. .sub.1, C.sub.1, .sub.2, C.sub.2 and .sub.3, C.sub.3 are the corresponding wavelengths and colours at higher angle of observation. The dominant colour M.sub.D of the coating is situated at .sub.D whose position depends on the relative intensity of all reflection peaks. FIG. 9B: Principle of colour stability represented on the 1931 C.I.E. chromaticity diagram. M is the resultant colour of a coating characterised by 3 reflection peaks, in the visible part of the solar spectrum, defined by C.sub.1, C.sub.2 and C.sub.3 at low angle of vision. C.sub.1, C.sub.2 and C.sub.3 are the corresponding colours for higher angle of vision. M.sub.D is the dominant colour of M.

(16) FIG. 10:

(17) Angular stability of 1931 CIE (x, y) colour coordinates under CIE-D65 illuminant of the coloured design given in Example 2.

(18) FIG. 11:

(19) Reflectance curves of the coating design given in Example 2 for various angles of reflection (from 0 to 85).

(20) FIG. 12:

(21) Angular stability of 1931 CIE (x, y) colour coordinates under CIE-D65 illuminant of the coloured design given in Example 3.

(22) FIG. 13:

(23) Reflectance curves of the coating design given in Example 3 for various angles of reflection (from 0 to 85).

(24) FIG. 14:

(25) Angular stability of 1931 CIE (x, y) colour coordinates under CIE-D65 illuminant of the coloured design given in Example 4.

(26) FIG. 15:

(27) Reflectance curves of the coating design given in Example 4 for various angles of reflection (from 0 to 85).

(28) FIG. 16:

(29) Angular stability of 1931 CIE (x, y) colour coordinates under CIE-D65 illuminant of the coloured design given in Example 5.

(30) FIG. 17:

(31) Reflectance curves of the coating design given in Example 5 for various angles of reflection (from 0 to 85).

(32) FIG. 18:

(33) Angular stability of 1931 CIE (x, y) colour coordinates under CIE-D65 illuminant of the coloured design given in Example 6.

(34) FIG. 19:

(35) Reflectance curves of the coating design given in Example 6 for various angles of reflection (from 0 to 85).

(36) FIG. 20:

(37) Angular stability of 1931 CIE (x, y) colour coordinates under CIE-D65 illuminant of the coloured design given in Example 7.

(38) FIG. 21:

(39) Reflectance curves of the coating design given in Example 7 for various angles of reflection (from 0 to 85).

(40) FIG. 22:

(41) Angular stability of 1931 CIE (x, y) colour coordinates under CIE-D65 illuminant of the coloured design given in Example 8.

(42) FIG. 23:

(43) Reflectance curves of the coating design given in Example 8 for various angles of reflection (from 0 to 85).

(44) FIG. 24:

(45) Angular stability of 1931 CIE (x, y) colour coordinates under CIE-D65 illuminant of the coloured design given in Example 9.

(46) FIG. 25:

(47) Reflectance curves of the coating design given in Example 9 for various angles of reflection (from 0 to 85).

(48) FIG. 26:

(49) Normal hemispherical transmittance measurements of a glass etched by solution 1 (ABF/IPA/H.sub.2O=30/10/6015 min etch time), a glass etched by solution 2 (ABF/sucrose/H.sub.2O=18/18/6415 min etch time) and an untreated glass. The normal hemispherical transmittance is around 95% for both etched glasses and around 92% for the untreated glass.

(50) FIGS. 27A, 27B:

(51) SEM pictures of glass surfaces structured by ABF-based etching solutions:

(52) FIG. 27A: ABF/IPA/H.sub.2O=30/10/6015 min etch time

(53) FIG. 27B: ABF/sucrose/H.sub.2O=18/18/6415 min etch time.

(54) FIGS. 28A, 28B, and 28C:

(55) Possible variations for the mounting of thermal or PVT solar systems glued behind a coloured laminated glazing: FIG. 28Aexample of roof installation with glazing overlap, FIG. 28Bexample of installation for residential ventilated facade, FIG. 28Cexample of adaptation to large buildings with glass facades.

(56) FIG. 29:

(57) Illustration of the reflection angle .sub.r, incidence angle .sub.l and transmission angle .sub.t.

EXAMPLES OF COATING DESIGNS

Example 1

(58) air//136 nm of L/222 nm of H//glass//222 nm of H/136 nm of L//air

(59) with n.sub.H=1.54 and n.sub.L=1.8

Example 2

(60) air//glass//30 nm of H/25 nm of L/320 nm of H//polymer

(61) with n.sub.H=2.4 and n.sub.L=1.65

Example 3

(62) air//glass//18512 nm of H/2512 nm of L/3512 nm of H/3512 nm of L/13012 nm of H//polymer

(63) with n.sub.H=2.4 and n.sub.L=2.0

Example 4

(64) air//glass//16012 nm of H/13012 nm of L/6512 nm of H/2512 nm of L/7012 nm of H/16012 nm of L/10012 nm of H//polymer

(65) with n.sub.H=2.2 and n.sub.L=2.0

Example 5

(66) air//glass//4512 nm of H/7012 nm of L/4512 nm of H//polymer

(67) with n.sub.H=2.0 and n.sub.L=1.65

Example 6

(68) air//glass//17512 nm of H/8512 nm of L/5012 nm of H/2512 nm of L/30012 nm of H//polymer

(69) with n.sub.H=2.4 and n.sub.L=2.0

Example 7

(70) air//glass//12012 nm of H/12012 nm of L/9512 nm of H/9012 nm of L/9012 nm of H/9512 nm of L/10012 nm of H//polymer

(71) with n.sub.H=2.0 and n.sub.L=1.65

Example 8

(72) air//glass//4012 nm of H/7512 nm of L//polymer

(73) with n.sub.H=2.4 and n.sub.L=1.65

Example 9

(74) air//glass//5012 nm of H/9012 nm of L/6512 nm of H/5512 nm of L//polymer

(75) with n.sub.H=2.4 and n.sub.L=2.0