Glazing having switchable optical properties

Abstract

A glazing having switchable optical properties is described, including a transparent substrate having an outer surface and an inner surface, a reflection layer on the outer surface and/or on the inner surface and a switchable functional element arranged on the interior side with respect to the reflection layer. The reflection layer contains a material having a refractive index n.sub.R of 1.6 to 2.5. The product of the refractive index n.sub.R and the thickness d of the reflection layer is from 250 nm to 960 nm.

Claims

1. A glazing having switchable optical properties, comprising: a transparent substrate having an outer surface and an inner surface; a reflection layer on the outer surface and/or on the inner surface; and a switchable functional element arranged on the interior side relative to the reflection layer, wherein the functional element is an electrochromic, a thermochromic, a gasochromic, a photochromic, a photoelectrochromic, a thermotropic, a PDLC or an SPD functional element, wherein the reflection layer contains a material having a refractive index n.sub.R, wherein the product of the refractive index n.sub.R and a thickness d of the reflection layer is from 250 nm to 960 nm, and wherein the reflection layer is a single and homogeneous layer so that the reflection is not a layer structure of individual layers.

2. The glazing according to claim 1, wherein the refractive index is measured at a wavelength of 550 nm.

3. The glazing according to claim 1, wherein the substrate is bonded to a transparent cover pane having an outer surface and an inner surface via the inner surface by means of at least one thermoplastic intermediate layer, and wherein the functional element is arranged on the outer surface, on the inner surface, or in the thermoplastic intermediate layer.

4. The glazing according to claim 1, wherein the substrate is bonded to a transparent cover pane having an outer surface and an inner surface via the inner surface by means of at least one spacer, and wherein the functional element is arranged on the outer surface or on the inner surface.

5. The glazing according to claim 1, wherein the reflection layer is arranged on the outer surface and the functional element is arranged on the inner surface.

6. The glazing according to claim 1, wherein the reflection layer contains at least silicon nitride, tin oxide, silicon oxynitride, zinc oxide, zirconium oxide, aluminum nitride, indium tin oxide, tin zinc oxide, titanium zinc oxide, and/or titanium silicon oxide.

7. The glazing according to claim 1, wherein the product of the refractive index n.sub.R and the thickness d of the reflection layer is from 365 nm to 400 nm, or from 730 nm to 800 nm.

8. The glazing according to claim 7, wherein the product of the refractive index n.sub.R and the thickness d of the reflection layer is from 375 nm to 390 nm.

9. The glazing according to claim 7, wherein the product of the refractive index n.sub.R and the thickness d of the reflection layer is from 750 nm to 780 nm.

10. The glazing according to claim 1, wherein the product of the refractive index n.sub.R and the thickness d of the reflection layer is from 435 nm to 480 nm, or from 870 nm to 960 nm.

11. The glazing according to claim 10, wherein the product of the refractive index n.sub.R and the thickness d of the reflection layer is from 440 nm to 475 nm.

12. The glazing according to claim 10, wherein the product of the refractive index n.sub.R and the thickness d of the reflection layer is from 880 nm to 950 nm.

13. The glazing according to claim 1, wherein the product of the refractive index n.sub.R and the thickness d of the reflection layer is from 305 nm to 365 nm, or from 610 nm to 730 nm.

14. The glazing according to claim 13, wherein the product of the refractive index n.sub.R and the thickness d of the reflection layer is from 320 nm to 345 nm.

15. The glazing according to claim 13, wherein the product of the refractive index n.sub.R and the thickness d of the reflection layer is from 640 nm to 690 nm.

16. The glazing according to claim 1, wherein the product of the refractive index n.sub.R and the thickness d of the reflection layer is from 250 nm to 300 nm, or from 500 nm to 600 nm.

17. The glazing according to claim 16, wherein the product of the refractive index n.sub.R and the thickness d of the reflection layer is from 270 nm to 285 nm.

18. The glazing according to claim 16, wherein the product of the refractive index n.sub.R and the thickness d of the reflection layer is from 540 nm to 570 nm.

19. The glazing according to claim 1, wherein the substrate contains non-prestressed, partially prestressed, or prestressed glass, or clear plastics and/or mixtures thereof.

20. The glazing according to claim 19, wherein the substrate contains flat glass, float glass, quartz glass, borosilicate glass, or soda lime glass.

21. The glazing according to claim 19, wherein the substrate contains polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyester, or polyvinyl chloride.

22. The glazing according to claim 19, wherein the substrate has a thickness from 20 m to 10 mm.

23. A method, comprising: providing the reflection layer in the glazing according to claim 1; selecting a refractive index n.sub.R and selecting a thickness d, wherein the product of the refractive index n.sub.R and the thickness d of the reflection layer is from 250 nm to 960 nm; and thereby controlling the external reflection color.

24. The method of claim 23, wherein the refractive index n.sub.R ranges from 1.6 to 2.55.

25. A method for producing a glazing having switchable optical properties, comprising: providing a transparent substrate having an outer surface and an inner surface, a reflection layer on the outer surface and/or on the inner surface, and a switchable functional element arranged on the interior side relative to the reflection layer, wherein the functional element is an electrochromic, a thermochromic, a gasochromic, a photochromic, a photoelectrochromic, a thermotropic, a PDLC, or an SPD functional element, wherein the reflection layer contains a material having a refractive index, wherein the product of a refractive index n.sub.R and a thickness d of the reflection layer is from 250 nm to 960 nm, and wherein the reflection layer is a single and homogeneous layer so that the reflection is not a layer structure of individual layers; applying the reflection layer on the outer surface or on the inner surface of the transparent substrate; applying the switchable functional element on the outer surface or on the inner surface of a transparent cover pane or incorporating the switchable functional element into a thermoplastic intermediate layer; and bonding the transparent substrate to the transparent cover pane via the thermoplastic intermediate layer under the action of heat, vacuum, and/or pressure.

26. A method for producing a glazing having switchable optical properties, comprising: providing a transparent substrate having an outer surface and an inner surface, a reflection layer on the outer surface and/or on the inner surface, and a switchable functional element arranged on the interior side relative to the reflection layer, wherein the functional element is an electrochromic, a thermochromic, a gasochromic, a photochromic, a photoelectrochromic, a thermotropic, a PDLC, or an SPD functional element, wherein the reflection layer contains a material having a refractive index n.sub.R, wherein the product of the refractive index n.sub.R and the thickness d of the reflection layer is from 250 nm to 960 nm, and wherein the reflection layer is a single and homogeneous layer so that the reflection is not a layer structure of individual layers; applying the reflection layer on the outer surface or on the inner surface of the transparent substrate; applying the switchable functional element on the outer surface or on the inner surface of a transparent cover pane; and bonding the transparent substrate to the transparent cover pane via at least one spacer.

27. A method for producing a glazing having switchable optical properties, comprising: providing a transparent substrate having an outer surface and an inner surface, a reflection layer on the outer surface and/or on the inner surface, and a switchable functional element arranged on the interior side relative to the reflection layer, wherein the functional element is an electrochromic, a thermochromic, a gasochromic, a photochromic, a photoelectrochromic, a thermotropic, a PDLC, or an SPD functional element, wherein the reflection layer contains a material having a refractive index n.sub.R, wherein the product of the refractive index n.sub.R and a thickness d of the reflection layer is from 250 nm to 960 nm, and wherein the reflection layer is a single and homogeneous layer so that the reflection is not a layer structure of individual layers; applying the reflection layer on the outer surface of the transparent substrate; and applying the switchable functional element on the inner surface of the transparent substrate.

Description

(1) The invention is explained in detail with reference to drawings and exemplary embodiments. The drawings are schematic representations and are not true to scale. The drawings in no way restrict the invention. They depict:

(2) FIG. 1 a cross-section through a first embodiment of the glazing according to the invention having switchable optical properties,

(3) FIG. 2 a cross-section through another embodiment of the glazing according to the invention,

(4) FIG. 3 a cross-section through another embodiment of the glazing according to the invention,

(5) FIG. 4 a cross-section through another embodiment of the glazing according to the invention,

(6) FIG. 5 a cross-section through another embodiment of the glazing according to the invention,

(7) FIG. 6 a cross-section through another embodiment of the glazing according to the invention,

(8) FIG. 7 an exemplary embodiment of the method according to the invention with reference to a flowchart, and

(9) FIG. 8 another exemplary embodiment of the method according to the invention with reference to a flowchart.

(10) FIG. 1 depicts a cross-section through an embodiment of the glazing according to the invention having switchable optical properties. The glazing comprises a substrate 1 that is bonded via its inner surface (II) to the outer surface (III) of a cover pane 4 by means of a thermoplastic intermediate layer 5 to form a composite pane. The glazing moreover comprises another pane 6 that is bonded via a spacer 7 to the inner surface (IV) of the cover pane 4 to form an insulating glazing unit. The glazing is provided as the glazing of a building faade and is arranged, in the installed position, such that the outer surface (I) of the substrate 1 faces the external environment, and the other pane 6 faces the interior. The substrate 1, the cover pane 4, and the other pane 6 are made of soda lime glass and have thicknesses of 6 mm. The thermoplastic intermediate layer 5 made of polyvinyl butyral (PVB) has a thickness of 0.76 mm. The distance between the cover pane 4 and the other pane 6 defined by the circumferential spacers 7 is 12 mm.

(11) A reflection layer 2 made of silicon nitride with a thickness d of 190 nm is arranged on the inner surface (II) of the substrate 1. The refractive index n.sub.R of the silicon nitride is 2.02. The product of the refractive index n.sub.R and the thickness d of the reflection layer 2 is roughly 384 nm. In this embodiment, a green color of the light reflected into the external environment is obtained by means of the reflection layer 2.

(12) A functional element 3 is arranged on the outer surface (III) of the cover pane 4. The functional element 3 has, in the installed position of the glazing, a shorter distance to the interior than the reflection layer 2. In the context of the invention, the functional element 3 is, consequently, arranged on the interior side of the reflection layer 2. The functional element 3 is an electrically switchable, electrochromic functional element. The region around the functional element 3 identified by the circle is shown enlarged on the right. The functional element 3 includes, in the exemplary embodiment, with increasing distance from the cover pane 4, a first flat electrode 9 made of fluoride-doped tin oxide, an electrochromic functional layer 11 made of lithium-doped tungsten oxide, an electrolytic layer 14 made of Ta.sub.2O.sub.5, an ion storage layer 13 made of lithium-doped CeO.sub.2, and a second flat electrode 10 made of indium tin oxide (ITO). The first flat electrode 9 and the second flat electrode 10 are connected via conductors (not shown) to an external power supply. The transmittance of visible light through the functional layer 11 depends on the storage level of lithium ions and can be switched by the voltage applied to the flat electrodes 9, 10, because, depending on the voltage applied, lithium ions can migrate between the functional layer 11 and the ion storage layer 13 through the electrolytic layer 14.

(13) Without the reflection layer 2, the switching state of the functional element 3 would be discernible for an observer in the external environment from the color of the reflected light. In the case of a plurality of glazings each with a functional element 3 on a building faade, this can result in a nonuniform and, consequently, not very aesthetic color appearance of the faade, when the individual functional elements 3 have different switching states. By means of the reflection coating 2, a uniform external reflection color, independent of the switching state of the functional element, is obtained. The color, which can be adjusted by the refractive index n.sub.R and the thickness d of the reflection layer 2, is also independent of the observation angle. The color has, consequently, for a moving observer, no changes depending on the observation position. The reflection layer 2 also includes only a single layer such that the glazing is simple and economical to produce. These are major advantages of the invention.

(14) FIG. 2 depicts a cross-section through another embodiment of the glazing according to the invention having switchable optical properties. The substrate 1 is bonded to the outer surface (III) of a cover pane 4 via its inner surface (II) by means of a thermoplastic intermediate layer 5. The inner surface (IV) of the cover pane 4 is bonded to another pane 6 via a second thermoplastic intermediate layer 12. The substrate 1, the cover pane 4, and the thermoplastic intermediate layer 5 are configured as in FIG. 1. The second thermoplastic intermediate layer 12 is made of PVB and has a thickness of 0.76 mm.

(15) A functional element 3 is arranged on the inner surface (IV) of the cover pane 4. The functional element 3 is a thermochromic layer made of doped VO.sub.2. The functional element 3 is thermally switchable: VO.sub.2 changes upon exceeding a temperature of roughly 68 C. from a semi-conductive state with high transmittance of visible light to a conductive state with reduced transmittance of visible light. The temperature of the transition between the switching states can be reduced by dopants, for example, tungsten, for example, to roughly 29 C.

(16) A reflection layer 2 made of zirconium oxide (ZrO.sub.2) with a thickness d of 200 nm is arranged on the outer surface (I) of the substrate 1. The refractive index n.sub.R of the zirconium oxide is roughly 2.22. The product of the refractive index n.sub.R and the thickness d of the reflection layer 2 is 444 nm. A golden color of the light reflected into the external environment is obtained by means of the reflection layer 2 in this embodiment.

(17) The thermochromic material can, alternatively, also be incorporated, for example, into one of the thermoplastic intermediate layers 5, 12, which would then form the switchable functional element 3.

(18) FIG. 3 depicts a cross-section through another embodiment of the glazing according to the invention having switchable optical properties. The substrate 1 is bonded to the outer surface (III) of the cover pane 4 via its inner surface (II) by means of a thermoplastic intermediate layer 5. The substrate 1 and the cover pane 4 are configured as in FIG. 1. The thermoplastic intermediate layer 5 comprises a first thermoplastic film 5.1 and a second thermoplastic film 5.2. The thermoplastic films 5.1 and 5.2 are made of PVB and have, in each case, a thickness of 0.76 mm.

(19) A functional element 3 is arranged between the first thermoplastic film 5.1 and the second thermoplastic film 5.2. The functional element 3 is arranged, in the context of the invention, in the thermoplastic intermediate layer 5. The region around the functional element 3 identified by the circle is shown enlarged on the right. The functional element 3 is a PDLC functional element and comprises a functional layer 11 between a first flat electrode 9 and a second flat electrode 10. The flat electrodes 9,10 are connected via conductors (not shown) to an external power supply. The functional layer 11 contains liquid crystals that are embedded in a polymeric network. When a voltage is applied to the flat electrodes 9,10, the liquid crystals align themselves along a common direction and the transmittance of visible light through the functional layer 11 is increased.

(20) A reflection layer 2 made of tin oxide (SnO.sub.2) with a thickness d of roughly 165 nm is arranged on the inner surface (II) of the substrate 1. The refractive index n.sub.R of the tin oxide is roughly 2.00. The product of the refractive index n.sub.R and the thickness d of the reflection layer 2 is roughly 330 nm. A blue color of the light reflected into the external environment is obtained by means of the reflection layer 2.

(21) FIG. 4 depicts a cross-section through another embodiment of the glazing according to the invention having switchable optical properties. A reflection layer 2 is arranged on the outer surface (I) of the substrate 1. A functional element 3 is arranged on the inner surface (II) of the substrate 1. The region around the functional element 3 identified by the circle is shown enlarged on the right.

(22) The reflection layer 2 made of indium tin oxide (ITO) has a thickness d of 145 nm. The refractive index n.sub.R of the indium tin oxide is 1.92. The product of the refractive index n.sub.R and the thickness d of the reflection layer 2 is roughly 278 nm. A violet color of the light reflected into the external environment is obtained by means of the reflection layer 2 in this embodiment.

(23) The substrate 1 is bonded, via its inner surface (II) by means of a circumferential spacer 7 to another pane 6 to form an insulating glazing unit. A heat protection coating 8 is arranged on the surface of the other pane 6 turned toward the substrate 1. Heat protection coatings (also referred to as low-E coatings) are known per se and improve the thermal comfort in the interior. Such heat protection coatings include, for example, functional layers based on silver, which reflect parts of the solar radiation in the summer, in particular in the IR range, and reduce the emission of thermal radiation via the glazing in the winter.

(24) FIG. 5 depicts a cross-section through another embodiment of the glazing according to the invention having switchable optical properties. The substrate 1 is bonded via its inner surface (II) by means of a circumferential spacer 7 to the outer surface (III) of a cover pane 4. The substrate 1 and the cover pane 4 are configured as in FIG. 1.

(25) A thermochromic functional element 3 is arranged on the outer surface (III) of the cover pane 4. A reflection layer 2 is arranged on the outer surface (I) of the substrate 1. The functional element 3 and the reflection layer 2 are configured as in FIG. 2.

(26) FIG. 6 depicts a cross-section through another embodiment of the glazing according to the invention having switchable optical properties. The substrate 1 is bonded via its inner surface (II) to the outer surface (III) of a cover pane 4. A functional element 3 is arranged between the substrate 1 and the cover pane 4. The functional element 3 is arranged on the inner surface (II) of the substrate 1 and the outer surface (III) of the cover pane 4 such that the substrate 1 and the cover pane 4 are bonded via the functional element 3. The region around the functional element 3 identified by the circle is shown enlarged on the right. The functional element 3 is an electrically switchable functional element and includes a functional layer 11 between a first flat electrode 9 and a second flat electrode 10, with the first flat electrode 9 applied on the outer surface (III) and the second flat electrode applied on the inner surface (II). The flat electrodes 9,10 are connected via conductors (not shown) to an external power supply. A reflection layer 2 is arranged on the outer surface (I) of the substrate 1.

(27) FIG. 7 depicts an exemplary embodiment of the method according to the invention for producing a glazing having switchable optical properties.

(28) The bonding of the cover pane and the substrate can also be done, in an alternative embodiment, via at least one spacer.

(29) FIG. 8 depicts another exemplary embodiment of the method according to the invention for producing a glazing having switchable optical properties.

(30) It was unexpected and surprising for the person skilled in the art that, by means of the reflection layer according to the invention, which is simple and economical to apply, effective regulation of the external reflection color of a glazing having switchable optical properties can be obtained. The external reflection color is independent of the switching state of the glazing and of the observation angle and can be freely selected by the choice of the material and the thickness of the reflection layer.

LIST OF REFERENCE CHARACTERS

(31) (1) transparent substrate (2) reflection layer (3) switchable functional element (4) transparent cover pane (5) thermoplastic intermediate layer (5.2) first thermoplastic film (5.2) second thermoplastic film (6) other pane (7) spacer (8) heat protection coating (9) first flat electrode of the functional element 3 (10) second flat electrode of the functional element 3 (11) functional layer of the functional element 3 (12) second thermoplastic intermediate layer (13) ion storage layer of the functional element 3 (14) electrolytic layer of the functional element 3 I outer surface of the transparent substrate 1 II inner surface of the transparent substrate 1 III outer surface of the cover pane 4 IV inner surface of the cover pane 4