MXPA99002368A - Coated glass - Google Patents

Abstract

A high performance solar control glass comprises a glass substrate with a coating comprising a heat absorbing layer and a low emissivity layer of a metal oxide. Preferred heat absorbing layers absorb preferentially at wavelengths above 700 nm, and may be, for example, of non-stoichiometric or doped tungsten oxide, or of cobalt oxide, chromium oxide, iron oxide or vanadiam oxide. Preferred low emissivity layers are of semi-conductor metal oxide, for example doped tin oxide or doped indium oxide. Because of the nature of the layers, the coatings may be of neutral colour and be suitable for deposition on-line on the glass ribbon, during the glass production process, by pyrolytic methods for example chemical vapour deposition.

Description

COATED GLASS The invention relates to coated glass and, in particular, to coated glass for high performance solar control. There is a growing demand for solar control glasses, especially high performance solar control glasses, which exhibit a neutral color in both the reflection and the transmission. By "high performance" solar control glasses, we understand glasses that transmit a significantly greater percentage of incident light than the total energy of incident radiation (total solar heat). Glasses dyed in the body, which contain added iron, are capable of providing a high performance of solar control, but iron tends to stain the glass green, and this green dye is not always acceptable. The inclusion of further additives, for example, a combination of selenium and a metal oxide, such as cobalt oxide, can convert the green dye to a more neutral color, but at the cost of some loss of performance, ie with a increase in the proportion of incident heat: transmitted incident light.

Coatings incorporating silver layers, in combination with appropriate dielectric layers in multi-layer stacks, can deliver high-performance solar color products, close to neutral in both reflection and transmission, but have significant disadvantages. First, suitable silver layers are not susceptible to in-line deposition methods where the coating is applied to the hot glass ribbon, as it is produced, ie before being cut and removed from the production line, but applied by low-pressure techniques off line, such as electronic magnetron deposit. Second, such silver coatings have limited the physical durability required by the care and handling protection during the process, and the protection of the coated glass in the final product, for example, by glazing in a multiple glazing unit, with the coating facing the Air space of the unit. It would be convenient to have a coating which would provide a high performance solar control glaze, without the disadvantages of the aforementioned silver coatings, and preferably having a color close to the neutral in the reflection and transmission, or at least provide a alternative to the green colors of the reflection and transmission, characteristic of the glasses dyed in the body, of high performance, previously mentioned. In accordance with the present invention, a high-performance coated solar control glass is provided, comprising a glass substrate and a coating including a heat absorbing layer and a low emissivity layer comprising a metal compound. The invention is illustrated, but not limited, by the accompanying schematic drawings, in which: Figure 1 shows a section through a coated glass, according to one embodiment of the invention; Figure 2 shows a section through a coated glass, according to a second preferred embodiment of the invention; and Figure 3 shows a section through a double glazing unit, incorporating a coated glass, as illustrated in Figure 1.

Referring to Figure 1, a high performance solar control glass 1 comprises a glass substrate 11, preferably of clear float glass type, and a coating 12, comprising an absorbent heat layer 14 and a layer 13 Low emissivity of a metal compound. The embodiment shown in Figure 2 is similar to the embodiment of Figure 1, with a coated glass 2 comprising a glass substrate 21, preferably of clear float glass, and a coating 22. However, the coating 22 differs from the coating 12 in which it comprises, in addition to the heat absorbing layer 24 and the low emissivity layer 23, a sub-layer 25 which suppresses the iridescence, as discussed here below. Figure 3 illustrates a coated glass sheet 1, according to Figure 1, assembled in a parallel spaced relationship with a second glass sheet of glazed material 31, typically clear float glass, the glass sheets are spaced and sealed together by a spacing and sealing system 32, to form a double glazing unit 3, having an air space 33. The covering 12 faces the air space 33 of the unit. To increase performance, it is desirable that the heat absorbing layer of the coating, preferably absorb wavelengths above 700 nm; preferably, substantially it does not absorb in the visible region of the spectrum. The heat absorbing layer can be a substantially transparent conductive oxide layer with the tungsten oxide being preferred in view of the characteristic absorption peak exhibiting around 900 nm. Tungsten oxide exists in both conductive and dielectric forms. Stoichiometric tungsten oxide, 03 is a dielectric, which does not substantially absorb near infrared. The non-stoichiometric tungsten oxide, W03_x, where x is typically up to about 0.03 (preferably in the range of 0.005 to 0.025), and tungsten oxide with impurities, containing appropriate impurities of different valence, for example hydrogen, fluorine, an alkali metal, copper, silver or gold, are conductive and suitable for use in the practice of the present invention.

A layer of tungsten oxide, used as a heat absorbing layer, can be crystalline or amorphous. If it is crystalline, it is generally preferred to avoid too large a crystal size, so large that the crystals are responsible for causing a fogging appearance. Other heat-absorbing materials, which can be used to form the heat absorbing layer, include other metal oxides of color transmission, such as chromium oxide, cobalt oxide, iron oxide, molybdenum oxide, niobium and vanadium oxide; Mixtures of such metal oxides can also be used. The heat absorbing layer will normally have a thickness in the range of 50 to 500 nm, especially 80 to 200 nm. The low-emissivity layer is a layer of a metal compound, usually a metal oxide (as well as other low-emissivity compounds, such as metal nitrides and metal silicides that tend to have minor light transmissions), and a transparent semiconductor, for example, an indium, tin or zinc oxide with impurities. Preferred materials include the contaminated indium oxide and the tin oxide contaminated with fluorine. The low emissivity layer will normally have a thickness in the range of 100 to 600 nm (since the use of a thicker layer is likely to result in an unnecessary reduction in light transmission without sufficient reduction in the emissivity to be compensated), especially a thickness in the range of 200 to 500 nm. The low emissivity layer may have an emissivity of less than 0.4 (the numerical values of emissivity are referred to in this description and in the appended claims to normal emissivity values, measured in accordance with ISO10292: 1994, Annex A), although it is preferred to use a low emissivity layer that provides an emissivity of 0.2 or less. The low emissivity layer of the coating will normally overlap the heat absorbing layer, with the solar control glass glazed with the coating facing the interior of the glazed space (usual, but not necessarily, a building). The use of thin films, as in the present invention, can result in the appearance of interference and iridescence colors. To avoid or at least remedy the unwanted color, which results from interference effects, a sublayer that suppresses the color (which itself can be a combination of sublayers) can be applied to the glass before depositing the layers that they absorb heat and low emissivity. The composition and deposit of such sublayers that suppress iridescence was described in the published prior patents, which include GB 2 031 756B, UK 2 115 315B and EP 0 275 662B. Thus, according to a preferred aspect of the invention, one or more layers that suppress iridescence are incorporated under the coating comprising a heat absorbing layer and a low emissivity layer. An additional layer can be incorporated onto the coating, for example as an anti-reflective layer, but the use of such overlays can lead to a loss of low emissivity properties, ie an increase in emissivity, and is not usually preferred. . The heat absorbing layer and the low emissivity layer of the present invention can be deposited by known techniques, for example by electronic deposit, which include the electronic reactive deposit or by chemical vapor deposition. In fact, it is a major advantage of the invention that both of the above layers are susceptible to deposit by chemical vapor deposition techniques, which provide the possibility of applying the coating to a hot glass ribbon, during the glass production process . The methods of depositing layers that absorb heat by the chemical vapor deposition are described, for example, in patents EP 0 523 877 Al and EP 0 546 669 Bl, while methods for depositing layers of low emissivity of metal oxide by the chemical vapor deposit, are described, for example, in patents GB 2 026 454B and EP 0 365 239B. The invention is illustrated, but not limited, by the following Examples. In the Examples, as in the remainder of the description and the claims, the reported visible light transmissions were measured using the Illuminant C. The total solar heat transmissions reported were determined by measuring the solar spectral irradiation function (ASTM E87-891 ) representing the direct normal radiation incident on a surface at 37 ° north latitude (mass of air 1.5) EXAMPLE 1 A sublayer, which suppresses iridescence, comprising silicon, carbon and oxygen, with a thickness of 65 nm and a refractive index of about 1.7, was applied to a clear 3 mm float glass ribbon, as described in EP 0 275 662B. A sheet of glass, cut from the tape, was coated by the conventional reactive magnetron electronic deposit on the sublayer, with a layer of heat-absorbing tungsten oxide about 100 nm thick, contaminated with hydrogen, to supply a absorption peak of 70% at a wavelength of 910 nm (when measured on clear 3 mm float glass, in the absence of a sublayer). A layer of indium tin oxide, about 265 nm thick, which serves as a low emissivity layer and exhibits an electrical resistivity of 4 x 10"4 ohms-centimeters, was deposited on the tungsten oxide layer by The conventional reactive electronic deposit magnetron, using an indium and tin lens, containing 10 atomic percent tin, such indium tin oxide layer has an emissivity of about 0.08. following properties: Visible light transmission: 70.4% Total solar heat transmission: 55.9% In the incorporation of the coated glass sheet in a double glazing unit with a 3 mm glass sheet of the clear uncoated float glass and a space of air of 12 mm, and with the coating towards the air space, the resulting unit will have a transmission of visible light of 64% and a total transmission of the solar heat of the 4 4%, and exhibits the following colors of reflection and transmission under illumination (Illuminant C): _ __ _ Reflection ^ 572 = T? 46 Transmission -2.9 1.2 84 EXAMPLE 2 A sublayer system that suppresses iridescence, comprising an initial layer of tin oxide without impurities, of 25 nm thickness, and a silica layer with a thickness of 25 nm, was applied to a clear glass flotation ribbon 3 mm thick. A sheet of glass cut from the tape was coated by the conventional reactive magnetron electronic deposit on the sublayer, with a layer of heat-absorbing tungsten oxide, with lithium impurities, approximately 420 nm thick, to supply a cresa 70% absorption at a wavelength of 910 nm (when measured on a 3 mm float glass, in the absence of a sublayer). A layer of indium tin oxide, about 85 nm thick, which serves as a low emissivity layer and exhibits an electrical resistivity of 4 x 10"4 ohms-centimeter, was deposited on top of the tungsten oxide layer by The conventional reactive electronic deposit magnetron, using an indium tin lens containing 10 atomic percent of tin, The resulting coated glass sheet had the following properties: Visible light transmission: 69% Total solar heat transmission: 54% In the incorporation of the coated sheet in a double glazing unit with a 3 mm glass sheet of uncoated clear float glass and an air gap of 12 mm, and with the coating towards the air space, the resulting unit will have a visible light transmission of 63% and a total solar heat transmission of 41% and will exhibit the following colors of reflection and transmission under illumination (IIluminant C ): a * b * L * Reflection -3.6 -3.3 90 Transmission -9.3 5.1 84 EXAMPLE 3 A sublayer, which suppresses the iridescence, as described in Example 2, was applied to a flotation glass strip, 3 mm thick. A sheet of glass cut from the tapes was coated with a non-stoichiometric tungsten oxide layer, which absorbs heat, of about 104 nm in thickness by the electronic deposit magnetron of an oxide target. The oxidation state of tungsten in the tungsten oxide was determined corresponds to a tungsten oxide of the formula W02.98 • A coating of indium tin oxide, about 270 nm thick, which serves as a low emissivity layer, was deposited on the tungsten oxide layer by the conventional electronic deposit reactive magnetron, with the use of an indium tin lens containing 10 atomic percent of tin. In the incorporation of the coated glass sheet in a double glazing unit, with a 3 mm sheet of clear uncoated float glass, and an air space of 12.5 mm and with the coating towards the air space, the unit resulting will have a transmission of visible light of 66% and a total transmission of solar heat of 46% and exhibits the following colors of reflection and transmission, under illumination (Illuminant C) a * b * L * "Reflection -7.7 2.25 49 Transmission ~ 9 0.61 85 ~ EXAMPLES 4 TO 9 In each of this series of Examples, the optical properties of the clear 3 mm float glass, coated, and of a double glazing unit, comprising a coated glass sheet and a clear float glass sheet uncoated, 3 mm, with an area of 12.5 mm are and a coating towards the air space, were calculated from the known optical properties of the glass and coating layers. The structure of the coatings and the properties of the coated glasses are indicated in the attached Tables 1 and 2.

Tfrbi l Example 4 5 6 First coating layer 380 nm oxide 240 nm oxide 126 nm tungsten oxide 'tungsten1 tungsten' Second coating layer 320 nm of 260 nm oxide of ITO3 300 nm of ITO3 tin contaminated with fluorine2 Transmission of visible light from the leaf 74.4% 70.1% 60.1% of coated glass Total solar heat transmission of 53.5% 51.25% 49.3% coated glass sheet Emissivity of the glass sheet 0.12-0.2 0.08 0.07 coated Transmission of visible light of 66.6% 63.6% 55.0% double glazing unit Total solar heat transmission of 41.8% 41.2% 41.0% double glazing unit Reflex color of the double unit of a * -8.3, b * 5.9, L 44 to * 0.5, b * 1.4, L 53 to * -2.3, b * 3.2, L 56 glaze Transmission color of the unit a * -6.3, b * 7.9, L 86 a * -6.8, b * 8.2, L 83 a * -6.4, b * 7.6, L 72 double glaze Table 2 Ejeírip? O 7 8 9 First coating layer 96 n oxide 380 nm oxide 240 nm tungsten oxide 'tungsten1 tungsten1 Second coating layer 300 nm of ITO3 320 nm of 260 nm oxide of ITO3 tin contaminated with fluorine2 Visible light transmission of the sheet 56.3% 71.3% 68.2% of coated glass Total solar heat transmission of 45.6% 54.6% 53.1% coated glass sheet Emissivity of glass sheet 0.07 0.12-0.2 0.08 coated Transmission of visible light of 51.3% 64.1% 61.0% double unit of glaze Total solar heat transmission of 35.2% 42.7% 42.5% double glazing unit Reflection color of the double unit of a * -4.3, b * 2.1, L 59 a * -8.0, b * 6.1, L 43 a * -0.6, b * 1.1, L 54 glaze Transmission color of the unit a * -5.3, b * 6.1, L 68 to * -6.4, b * 7.3, L873 to * -7.2, b * 7.9, L 85 double glaze 1 Properties of non-stoichiometric tungsten oxide deposited electronically by the magnetron of, used in the calculation 2 Properties of tin oxide coating contaminated with fluorine, deposited by the chemical vapor deposit in the calculation 3 Properties of the coating of indium oxide contaminated with tin, deposited electronically by the magnetron of, with electrical resistivity of 1.8 x 104 Ocm, used in the calculation. 4 Properties of niobium pentoxide deposited electronically by magnetron, contaminated with atomic 30% lithium, used in the calculation.

The coatings of the present invention offer important advantages over the prior art.

Being suitable for a production by pyrolytic methods (which have the added benefit of driving by themselves to the online application) they can be obtained in a highly durable way, reducing the need of the city or special in the handling and process and opening the possibility to use the coatings in the free-standing glaze, without the need to protect them with multiple units of glaze. Compared to stained glasses in the body, they offer the advantages of being suitable for production by a more flexible technique (coating) applicable without the need to change the composition in the glass melting tank (with the inherent loss of the production as the exchange takes place), and avoid the strong green tints observed with the high performance body tints. Also, excellent performances can be achieved, with the glasses having a visible light transmission greater than 67%, providing a total solar heat transmission of less than 57%. In general, the solar control glazes of the present invention will provide a total solar heat transmission at least 10% less than the transmission of visible light, while the glazes provide a total solar heat transmission of at least 12% below ( at least 15% below, when the coated glass is used with a clear float glass sheet in a double glazing unit) can be easily achieved and are preferred. The preferred coated glasses of the present invention are glasses in which the coating is such that it exhibits reflection (when viewed from the coated side) and transmission (when applied to clear float glass), colors such as (a * 2 + b * 2) are less than 12, especially less than 10. In especially preferred embodiments, at least one of the reflected and / or (preferably and) transmission colors is such that (a * 2 + b * 2) M is less of 7.

Claims (25)

1. REVIVAL APPLICATIONS 1. A coated, high performance solar control glass comprising a glass substrate with a coating that includes a heat absorbing layer and a low emissivity layer of a metal compound.
2. 2. A coated glass, according to claim 1, wherein the heat absorbing layer of the coating preferably absorbs wavelengths greater than 700 nm.
3. 3. A coated glass, according to claim 1, wherein the heat absorbing layer of the coating is a layer of metal oxide.
4. 4. A coated glass, according to claim 1, wherein the heat absorbing layer of the coating is a layer of tungsten oxide, which contains a less than stoichiometric amount of oxygen.
5. 5. A coated glass, according to any of claims 1 to 4, wherein the heat absorbing layer of the coating is tungsten oxide contaminated with hydrogen.
6. 6. A coated glass, according to any of claims 1 to 5, wherein the heat absorbing layer of the coating is tungsten oxide contaminated with an alkali metal.
7. 7. A coated glass, according to any of claims 1 to 5, wherein the heat-absorbing layer of the coating is chromium oxide, cobalt oxide, iron oxide, molybdenum oxide, niobium oxide, vanadium oxide, or its mixtures.
8. 8. A coated glass, according to any of the preceding claims, wherein the heat absorbing layer of the coating has a thickness in the range of 50 to 500 nm.
9. 9. A coated glass, according to any of the preceding claims, wherein the heat absorbing layer of the coating has a thickness in the range of 80 to 200 nm.
10. 10. A coated glass, according to any of the preceding claims, having an emissivity of less than 0.4.
11. 11. A coated glass, according to claim 10, having an emissivity of less than 0.2.
12. 12. A coated glass, according to any of the preceding claims, wherein the low emissivity layer is an oxide of a semiconductor metal.
13. 13. A coated glass, according to claim 12, wherein the oxide of the semiconducting metal is tin oxide or indium oxide contaminated.
14. 14. A coated glass, according to claims 12 or 13, wherein the low emissivity layer has a thickness in the range of 10 to 600 nm.
15. 15. A coated glass, according to claim 14, wherein the low emissivity layer has a thickness in the range of 200 to 500 nm.
16. 16. A coated glass, according to any of the preceding claims, wherein the low emissivity layer of the coating overlaps the heat absorbing layer.
17. 17. A coated glass, according to claim 16, wherein the coating further comprises one or more layers that suppresses the iridescence, under the heat absorbing layer.
18. 18. A coated glass, according to any of the preceding claims, which exhibits a total solar heat transmission of at least 10% less than its transmission of visible light.
19. 19. A coated glass, according to claim 18, which exhibits a transmission of visible light greater than 67% and a total solar heat transmission of less than 57%.
20. 20. A coated glass, according to any of the preceding claims, wherein the coating is such as to exhibit reflection colors (when viewed from the coated side) and / or transmission (when applied to clear float glass), which are each in such a way that (a * 2 + b * 2) is less than 12.
21. 21. A coated glass, according to claim 20, wherein the coating is such as to exhibit a reflection color (when viewed from the coated side) and / or transmission (when applied to a clear float glass) so that (a * 2 + b * 2) is less than 7.
22. 22. A coated glass for solar control, high performance, comprising a glass substrate and a coating, including a heat absorbing layer and a low emissivity layer, substantially as described above with reference to any of Examples 1 to 9.
23. 23. A multiple glazing unit, comprising a coated glass sheet, as claimed in any of the preceding claims, in a parallel and spaced relationship with a second glazing sheet.
24. 24. A multiple glazing unit, as claimed in claim 23, which exhibits a total solar heat transmission of at least 15% less than its transmission of visible light.
25. 25. A multiple glazing unit, comprising a glass sheet for high performance solar control, substantially as described above, with reference to any of the Examples 1