WO2017212214A1

WO2017212214A1 - Coated glass article and window for a vehicle including the same

Info

Publication number: WO2017212214A1
Application number: PCT/GB2017/051439
Authority: WO
Inventors: Neil Mcsporran; Srikanth Varanasi; Kyle Erik SWORD
Original assignee: Pilkington Group Limited
Priority date: 2016-06-09
Filing date: 2017-05-23
Publication date: 2017-12-14

Abstract

A coated glass article includes a glass substrate and a coating formed on the glass substrate. The coating includes a first inorganic metal oxide layer deposited over a major surface of the glass substrate. The first inorganic metal oxide layer includes fluorine doped tin oxide. A second inorganic metal oxide layer is deposited between the first inorganic metal oxide layer and the glass substrate. The second inorganic metal oxide layer includes antimony doped tin oxide. The coated glass article exhibits a visible light transmittance (llluminant A, 2 degree observer) of 35% or less.

Description

COATED GLASS ARTICLE AND

WINDOW FOR A VEHICLE INCLUDING THE SAME

CROSS-REFERENCE TO RELATED APPLICATION This application is claiming the benefit, under 35 U.S. C. 1 19(e), of the provisional U.S. patent application which was granted Serial No. 62/347,763 and filed on June 9, 2016, the entire disclosure of which is hereby incorporated by reference.

BACKGROUND

The invention relates to a coated glass article. The invention also relates to a window for a vehicle including the coated glass article.

The windows of a vehicle are a prominent feature in the overall design of the vehicle. Increasingly, there is interest in reducing the solar gain into the vehicle that occurs in hot weather and reducing the heat lost from the vehicle that occurs in cold weather. Also, there is interest in maintaining or improving the visual comfort of the passengers by reducing the visible light transmittance into the passenger cabin of the vehicle. To address these issues window manufacturers have increased the thickness and absorbance of vehicle windows. However, such windows add weight to the vehicle which reduces the vehicle's fuel efficiency. Also, such windows are expensive and complex to manufacture.

Thus, it would be desirable to provide a vehicle window that has a low visible light transmittance, reduces solar gain and heat loss when desired, and is easier and less expensive to manufacture.

BRIEF SUMMARY OF THE INVENTION

Embodiments of a coated glass article are provided.

In an embodiment, the coated glass article comprises a glass substrate and a coating formed on the glass substrate. The coating comprises a first inorganic metal oxide layer deposited over a major surface of the glass substrate. The first inorganic metal oxide layer comprises fluorine doped tin oxide. A second inorganic metal oxide layer is deposited between the first inorganic metal oxide layer and the glass substrate. The second inorganic metal oxide layer comprises antimony doped tin oxide. The coated glass article exhibits a visible light transmittance (llluminant A, 2 degree observer) of 35% or less.

In another embodiment, the coated glass article comprises a glass substrate and a coating formed on the glass substrate. The coating comprises

a first inorganic metal oxide layer deposited over a major surface of the glass substrate. The first inorganic metal oxide layer comprises fluorine doped tin oxide. A second inorganic metal oxide layer is deposited between the first inorganic metal oxide layer and the glass substrate. The second inorganic metal oxide layer comprises antimony doped tin oxide. A third inorganic metal oxide layer is deposited between the second inorganic metal oxide layer and the glass substrate. A fourth inorganic metal oxide layer is deposited between the third inorganic metal oxide layer and the glass substrate. The fourth inorganic metal oxide layer comprises antimony doped tin oxide. A fifth inorganic metal oxide layer is deposited between the fourth inorganic metal oxide layer and the glass substrate. The fifth inorganic metal oxide layer comprises silicon dioxide and is deposited at a thickness of 15 - 60 nm. The coated glass article exhibits a visible light transmittance, (llluminant A, 2 degree observer) of 35% or less and a direct solar energy transmittance of 25% or less.

BRIEF DESCRIPTION OF THE DRAWINGS

The above, as well as other advantages of the present invention will become readily apparent to those skilled in the art from the following detailed description when considered in the light of the accompanying drawings in which:

FIG. 1 is a cross-sectional view of an embodiment of a coated glass article in accordance with the invention;

FIG. 2 is a cross-sectional view of another embodiment of the coated glass article in accordance with the invention;

FIG. 3 is a partial perspective view of vehicle depicting a window assembly including the coated glass article of either FIG. 1 or FIG. 2; and

FIG. 4 is a schematic view, in vertical section, of an installation for practicing the float glass manufacturing process in accordance with certain embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

It is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific articles, assemblies and features illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts.

Hence, specific dimensions, directions, or other physical characteristics relating to the embodiments disclosed are not to be considered as limiting, unless expressly stated otherwise. Also, although they may not be, like elements in various embodiments described herein may be commonly referred to with like reference numerals within this section of the application.

Embodiments of a coated glass article 10, 10A are illustrated in FIGs. 1 and 2. As illustrated in FIG. 3, the embodiments of the coated glass article 10, 10A may be utilized in a window 12 for a vehicle 14. It would be understood by one of ordinary skill in the art that the window described herein may have applications to on-highway and off-highway vehicles. Also, the coated glass article could be utilized in a commercial or residential glazing or have, for example, architectural, photovoltaic, industrial, locomotive, naval and aerospace applications.

The window 12 may be installed in any appropriate body opening of the vehicle 14. However, it is preferred that the window 12 is installed in a body opening 16 of the vehicle 14 so as to be a side window or rear window of the vehicle. In other embodiments (not depicted), the window could be utilized in another body opening in the vehicle. For example, the window could be installed in an opening in the roof of the vehicle. In this embodiment, the window is a roof lite of the vehicle.

Referring back to FIGs. 1 and 2, the coated glass article 10, 10A comprises a glass substrate 18. The glass substrate 18 is not limited to a particular thickness. However, in certain embodiments, it may be preferred that the thickness of the glass substrate 18 is 3 - 6 millimeters (mm). Also, the glass substrate 18 may be of any of the conventional glass compositions known in the art. However, in certain embodiments, the composition of the glass substrate 18 may be selected to allow the coated glass article 10, 10A to exhibit certain specific spectral properties. Preferably, the glass substrate 18 is a soda-lime-silica glass. In this embodiment, the substrate 18 may be a float glass ribbon. However, the glass substrate may be of another composition such as, for example, a borosilicate or aluminosilicate composition. Also, the transparency or absorption characteristics of the glass substrate may vary between embodiments of the coated glass article.

The color of the glass substrate 18 can vary between embodiments of the coated glass article 10, 10A. In an embodiment, the glass substrate 18 may be substantially clear and transparent to visible light. In other embodiments, it is preferred that the glass substrate 18 is colored. In these embodiments, it is preferred that the glass substrate is of a grey, grey-blue, or green color. However, it should be appreciated that the glass substrate may be of another color such as, for example, blue-green or bronze.

When the glass substrate 18 is of a grey color, the glass substrate 18 may comprise 0.1 - 2.0 weight % Fe₂0₃ (total iron). Preferably, when the glass substrate 18 is of a grey color, the glass substrate 18 comprises 1 .2 - 2.0 weight % Fe₂0₃ (total iron). As used herein, the phrase "total iron" refers to the total weight of iron contained in the glass batch, before reduction, utilized to make the glass substrate. Also, in these embodiments, the glass substrate 18 may have an a^* value of -5±5, preferably -4±3, a b^* value of 0±10, preferably 4±1 and an L^* of 50±10, preferably 50±5 in the CIELAB color scale system. In these embodiments, the grey glass substrate may have a transmission of 50% or less for visible light wavelengths of the electromagnetic spectrum when the glass substrate 18 has a nominal thickness of 6 mm. For example, in certain embodiments, the grey glass substrate has a transmission of 39 - 48% for visible light wavelengths of the electromagnetic spectrum when the glass substrate 18 has a nominal thickness of 6 mm. Alternatively, in other embodiments, the grey glass substrate has a transmission of 7 - 1 1 % for visible light wavelengths of the electromagnetic spectrum when the glass substrate 18 has a nominal thickness of 6 mm . In still other embodiments, when the glass substrate 18 is of a grey color, the glass substrate is a sheet of glass as described in one of U.S. patent nos. 5,308,805, 5,650,365 or 5,747,398, the entire disclosures of which are incorporated herein in their entirety. Preferably, the grey glass substrate 18 is a sheet of glass sold under the trademark Pilkington Optifloat Grey and sold by Pilkington or is a sheet of glass having similar optical properties. In other embodiments, when the glass substrate 18 is of a grey color, the glass substrate is a sheet of glass sold under the trademark Pilkington Galaxsee and is sold by Pilkington or is a grey colored glass substrate having similar optical properties.

When the glass substrate 18 is of a grey-blue color, the glass substrate 18 may comprise one or more colorants. For example, in an embodiment, the glass substrate 18 comprises 0.30 - 0.40 weight % Fe₂0₃, 46 - 60 ppm Co₃0₄, and 1 - 5 ppm Se. Also, when the glass substrate 18 is of a grey-blue color, the glass substrate may have an a^* value of -4 - -2, preferably -3 - -2, a b^* value of -9 - -5, preferably -7 - -6 and an L^* of 80 - 84, preferably 81 - 83 in the CIELAB color scale system. In these embodiments, the grey-blue glass substrate 18 may have a transmission of 55 - 65% for visible light wavelengths of the electromagnetic spectrum when the inner pane of glass has a nominal thickness of 6 mm. In other embodiments, when the glass substrate 18 is of a grey-blue color, the inner pane of glass is a sheet of glass as described in U.S. patent publication no. US 2015/0329407, the entire disclosure of which is hereby incorporated by reference in its entirety. Preferably, in these embodiments, the grey-blue colored glass substrate 18 is a sheet of glass sold under the trademark Pilkington Optifloat Graphite Blue and sold by Pilkington or is a grey-blue colored glass substrate having similar optical properties.

When the glass substrate 18 is of a green color, the glass substrate 18 may comprise 0.45 - 1 .0 weight % Fe₂0₃ (total iron). Preferably, when the glass substrate 18 is of a green color, the glass substrate 18 comprises 0.6 - 1 .0 weight % Fe₂0₃ (total iron). Also, in these

embodiments, the glass substrate 18 may have an a^* value of -10±10, preferably -8±4, a b^* value of 4±5, preferably 2+3/-2 and an L^* of 89±10, preferably 89±2 in the CIELAB color scale system (llluminant A, 2 degree observer). In these embodiments, the grey glass substrate may have a visible light transmission (llluminant A, 2 degree observer) of more than 70% when the glass substrate 18 has a thickness of 3 - 5 mm. In still other embodiments, when the glass substrate 18 is of a green color, the glass substrate is a sheet of glass as described in one of U.S. patent nos. 5,641 ,716 or 5,077,133, the entire disclosures of which are incorporated herein in their entirety. Preferably, the green glass substrate 18 is a sheet of glass sold under the trademark Pilkington EZ-KOOL and sold by Pilkington or is a sheet of glass having similar optical properties. In other embodiments, when the glass substrate 18 is of a green color, the glass substrate is a sheet of glass sold under the trademark Pilkington EverGreen and is sold by Pilkington or is a green colored glass substrate having similar optical properties. A coating 20, 20A is formed on the glass substrate 18. In an embodiment, the coating 20, 20A is pyrolytic. Preferably, the coating 20, 20A is formed on a first major surface 22 of the glass substrate 18. A side of the glass substrate 18 where the coating 20, 20A is formed may be referred to herein as the coated side. Preferably, a second major surface 24 of the glass substrate 18 and an opposite side of the coated glass article 10, 10A is uncoated. When the coated glass article 10, 10A is utilized in a window for a vehicle, it is preferred that the first major surface 22 and the coating 20, 20A face into the passenger cabin of the vehicle 14.

In certain embodiments, the coating is conductive. In these embodiments, it is preferred that the coating 20, 20A is formed so as to exhibit a sheet resistance of 5 - 50 ohm/sq.

Preferably, the coating 20, 20A comprises one or more inorganic metal oxide layers. In an embodiment, the coating 20, 20A comprises a first inorganic metal oxide layer 26 and a second inorganic metal oxide layer 28. In another embodiment, the coating 20, 20A comprises the first coating layer 26, the second coating layer 28, a third inorganic metal oxide layer 30, and a fourth inorganic metal oxide layer 32, 32A. In the embodiment illustrated in FIG. 1 , the coating 20 may consist of the four coating layers 26, 28, 30, 32. However, in other embodiments, like the one illustrated in FIG. 2, the coating 20A also comprises a fifth inorganic metal oxide layer 34A. In this embodiment, the coating 20A may consist of five coating layers 26, 28, 30, 32A, 34A.

The coating 20, 20A and one or more of its layers 26, 28, 30, 32, 32A, 34A may be formed in conjunction with the manufacture of the glass substrate 18. Preferably, in these embodiments, the glass substrate 18 is formed utilizing the well-known float glass manufacturing process. The coating layers 26, 28, 30, 32, 32A, 34A may be deposited by any suitable method but are preferably deposited by atmospheric chemical vapor deposition (APCVD). However, other known deposition methods are suitable for depositing one or more of the coating layers such as, for example, sol-gel coating techniques or sputter coating techniques. In embodiments where the substrate 18 is a float glass ribbon, the coating 20, 20A is preferably formed in the heated zone of the float glass manufacturing process.

The first coating layer 26 is deposited over the first major surface 22 of the glass substrate 18. The first coating layer 26 is also deposited over and, preferably, directly on the second coating layer 28. The first coating layer 26 may be the outermost layer of the coating 20, 20A. When the first coating layer 26 is the outermost layer of the coating 20, 20A, the first coating layer 26 forms the outer surface 36 of the coated glass article 10, 10A.

In certain embodiments, the first coating layer 26 is pyrolytic. Preferably, the first coating layer 26 comprises an inorganic metal oxide. In an embodiment, the first coating layer 26 comprises fluorine doped tin oxide (Sn0₂:F) or another suitable inorganic metal oxide.

In certain embodiments, the first coating layer 26 is deposited on the second coating layer 28 at a thickness of 150 nm or more. Preferably, in the embodiments illustrated in FIGs. 1 and 2, the first coating layer 26 is fluorine doped tin oxide and is deposited at a thickness of 150 - 400 nm. More preferably, in these embodiments, the thickness of the first coating layer 26 is 200 - 300 nm.

The second coating layer 28 is deposited between the first coating layer 26 and the glass substrate 18. The second coating layer 28 is deposited over and, preferably, directly on the third coating layer 30. Thus, the second coating layer 28 separates the first coating layer 26 from the third coating layer 30.

In certain embodiments, the second coating layer 28 is pyrolytic. In an embodiment, like the one illustrated in FIG. 1 , the second coating layer 28 has a refractive index that is greater than the refractive index of the third coating layer 30. In this embodiment, the second coating layer 28 has a refractive indexwhich is less than 2.1 and between 1.6 and 2.1 . For example, the refractive index of the second coating layer 28 may be about from about 1 .8 - 2.0. In these embodiments, it is preferred that the second coating layer 28 comprises an inorganic metal oxide such as antimony doped tin oxide (Sn0_2:Sb). When the second coating layer 28 comprises antimony doped tin oxide, the molar ratio of antimony to tin in the second coating layer is 0.08 - 0.14. Preferably, when the second coating layer 28 comprises antimony doped tin oxide, the molar ratio of antimony to tin is 0.12. Also, in these embodiments, it is preferred that the second coating layer 28 is deposited on the third coating layer 30 at a thickness of 500 nm or less.

Preferably, in these embodiments, the second coating layer 28 is deposited on the third coating layer 30 at a thickness of 200 - 400 nm. More preferably, the second coating layer 28 is deposited on the third coating layer 30 at a thickness of 250 - 400 nm.

The third coating layer 30 is deposited between the second coating layer 28 and the glass substrate 18. The third coating layer 30 is deposited over and, preferably, directly on the fourth coating layer 32, 32A. Thus, the third coating layer 30 separates the second coating layer 28 from the fourth coating layer 32, 32A.

In certain embodiments, the third coating layer 30 is pyrolytic. In other embodiments, the third coating layer 30 has a refractive index that is less than the refractive index of the second coating layer 32, 32A. In this embodiment, the third coating layer 30 has a refractive indexwhich is 1.6 or less. For example, the refractive index of the third coating layer 30 may be about from about 1 .4 - 1 .6. In these embodiments, it is preferred that the third coating layer 30 comprises an inorganic metal oxide such silicon dioxide (Si0₂). Also, in these embodiments, is preferred that the third coating layer 30 is deposited on the fourth coating layer 32, 32A at a thickness of 60 nm or less. Preferably, in these embodiments, the third coating layer 30 is deposited on the fourth coating layer 32, 32A at a thickness of 15 - 60 nm. More preferably, the third coating layer 30 is deposited on the fourth coating layer 32, 32A at a thickness of 20 - 40 nm.

The fourth coating layer 32, 32A is deposited between the third coating layer 30 and the glass substrate 18. In the embodiment illustrated in FIG. 1 , the fourth coating layer 32 is deposited over and directly on the first major surface 22 of the glass substrate 18. Thus, in this embodiment, the fourth coating layer 32 separates the third coating layer 30 from the glass substrate 18. In the embodiment illustrated in FIG. 2, the fourth coating layer 32A is deposited over and directly on the fifth coating layer 34A. Thus, in the embodiment illustrated in FIG. 2, the fourth coating layer 32A separates the third coating layer 30 from the fifth coating layer 34A.

In certain embodiments, the fourth coating layer 32, 32A is pyrolytic. Preferably, the fourth coating layer 32, 32A is formed of an inorganic metal oxide. In certain embodiments, the fourth coating layer 32, 32A has a refractive index of 1.85 or less. In one such embodiment, the fourth coating layer 32, 32A comprises tin oxide or another suitable inorganic metal oxide. In these embodiments, the third coating layer 30 and the fourth coating layer 32, 32A provide an iridescence-suppressing interlayer that contributes to reducing the iridescence exhibited by the coating 20, 20A so that the coated glass article 10, 10A is neutral colored in both reflectance and transmittance.

In the embodiment illustrated in FIG.1 , it is preferred that the fourth coating layer 32 comprises undoped tin oxide (Sn0₂). In this embodiment, the fourth coating layer 32 has a refractive index of between 1.6 and 1.85. Preferably, when the fourth coating layer 32 comprises undoped tin oxide, the fourth coating layer 32 has a refractive index which is about 1 .8. Also, in these embodiments, the thickness of the fourth coating layer 32 is 15 - 60 nanometers (nm). Preferably, when the fourth coating layer 32 comprises undoped tin oxide, the thickness of the fourth coating layer 32 is 20 - 40 nm.

In the embodiment illustrated in FIG. 2, it is preferred that the fourth coating layer 32A comprises antimony doped tin oxide (Sn0_2:Sb). When the fourth coating layer 32A comprises antimony doped tin oxide, the fourth coating layer 32A contributes to reducing the iridescence exhibited by the coating 20A as described above and reduces the visible light transmittance through the coated glass article 10A. In this embodiment, the thickness of the fourth coating layer 32A is 100 - 150 nm. Preferably, when the fourth coating layer 32A comprises antimony doped tin oxide, the thickness of the fourth coating layer is 1 10 - 135 nm. Also, when the fourth coating layer 32A comprises antimony doped tin oxide, the molar ratio of antimony to tin is 0.08 - 0.14. Preferably, when the fourth coating layer 32A comprises antimony doped tin oxide, the molar ratio of antimony to tin is 0.12.

In the embodiment illustrated in FIG. 2, the fifth coating layer 34A is deposited between the fourth coating layer 32A and the glass substrate 18. Preferably, the fifth coating layer 34A is deposited over and directly on the first major surface 22 of the glass substrate 18. Thus, the fifth coating layer 34A separates the fourth coating layer 32A from the glass substrate 18. In this position, the fifth coating layer 34A helps to reduce the haze exhibited by the coated glass article 10A.

In certain embodiments, the fifth coating layer 34A is pyrolytic. Preferably, the fifth coating layer 34A is formed of an inorganic metal oxide. In an embodiment, the fifth coating layer 34A has a refractive index of 1 .6 or less. In these embodiments, the fifth coating layer 34A comprises silicon dioxide or another suitable inorganic metal oxide.

In the embodiments where the fifth coating layer 34A comprises silicon dioxide, the fifth coating layer has a refractive index of between 1 .4 and 1.6. Preferably, in these embodiments, the fifth coating layer 34A has a refractive indexwhich is about 1.46. Also, it is preferred that in these embodiments, the thickness of the fifth coating layer 34A is 15 - 60 nm. Preferably, the thickness of the fifth coating layer 34A is 20 - 40 nm .

The coated glass article 10, 10A exhibits advantageous properties. For example, the coated glass article 10, 10A may exhibit a low U-value. As used herein, the term U-value is a measure in Btu/hr/Sq-ft/°F of the heat gain or loss through the coated glass article due to environmental differences between the air on the opposite sides of the article. A low U-value means that when the coated glass article is used as a window for a vehicle the heat loss through the article from the passenger cabin to the exterior of the vehicle is low. Such a U-value may be calculated per NFRC 100 standard using LBLW4.1 . In an embodiment, the coated glass article 10, 10A exhibits a U-value of 0.60 or less. Preferably, the coated glass article 10, 10A exhibits a

U-value of 0.50 or less. In this embodiment, the coated glass article 10, 10A may exhibit a U- value of 0.35 - 0.50.

As another example, the coated glass article 10, 10A may exhibit an emissivity of less than 0.20 and, preferably, 0.15 - 0.16. At this emissivity, when the coated glass article 10, 10A is utilized in a window for a vehicle, the coated glass article provides an insulating effect for the passenger cabin of the vehicle. The coated glass article 10, 10A may also exhibit an improved solar heat gain coefficient and total solar heat transmission when compared to the prior art designs. As used herein, the term solar heat gain coefficient (SHGC) is the ratio of total solar heat gain through the coated glass article relative to the incident solar radiation. Preferably, the coated glass article exhibits an SHGC of 0.35 or less. Also, as used herein, the term total solar heat transmittance (TSHT) is defined as including solar energy transmitted directly through the coated glass article and the solar energy absorbed by the article, and subsequently convected and thermally radiated inwardly. Preferably, the coated glass article 10, 10A exhibits a TSHT of 35 or less. In certain embodiments, the coated glass article 10, 10A may exhibit a TSHT of 30 or less.

Also, the coated glass article 10, 10A exhibits an improved solar energy transmittance. As used herein, direct solar energy transmittance (Tsol) refers to solar transmittance integrated over the wavelength range 300 to 2500 nm according to the relative solar spectral distribution for air mass 1 .5. In an embodiment, the coated glass article 10, 10A may exhibit a direct solar energy transmittance of less than 25%. Preferably, the coated glass article 10, 10A exhibits a direct solar energy transmittance of 20% or less and, in certain embodiments, 5% or less. The embodiments of the coated glass article 10, 10A also exhibit an advantageous total visible light transmittance. For example, when the coated glass article 10, 10A is utilized in a window for a vehicle, the total visible light transmittance exhibited by the coated glass article improves the visual comfort of the passengers by providing a reduced visible light transmittance into the passenger cabin of the vehicle. For describing the coated glass article 10, 10A, total visible light transmittance will refer to the percentage of visible light passing through the article as measured from a side 38 facing the coating 20, 20A and according to the CIELAB color scale system using llluminant A, 2 degree observer. In the embodiments described above, the coated glass article 10, 10A exhibits a total visible light transmittance (llluminant A, 2 degree observer) of 35% or less. Preferably, the coated glass article 10, 10A exhibits a total visible light

transmittance (llluminant A, 2 degree observer) of 30% or less. More preferably, the coated glass article 10, 10A exhibits a total visible light transmittance (llluminant A, 2 degree observer) of 25% or less. Even more preferably, the coated glass article 10, 10A exhibits a total visible light transmittance (llluminant A, 2 degree observer) of 20% or less.

In still other embodiments, the coated glass article 10, 10A may exhibit a neutral color for the visible light reflected from the uncoated side of the coated glass article 10, 10A when measured from a side 40 facing the uncoated side of the coated glass article 10, 10A and viewed at a 90 degree angle incident from the article. In further embodiments, the coated glass article 10, 10A may exhibit a neutral color for the visible light transmitted through the coated glass article 10, 1 OA when viewed at a 90 degree angle incident from the article. For the purpose of describing the embodiments of the coated glass article 10, l OA disclosed herein, a neutral color for the visible light reflected from or transmitted through the coated glass article is defined under the CIELAB color scale system (llluminant A, 2 degree observer) with an a^* value in the range of - 6 to 6 and a b^* value in the range of -6 to 6. It is preferred that the visible light reflected from or transmitted through the coated glass article 10, 10A has an a^* (llluminant A, 2 degree observer) of -3 to 3 and a b^* value (llluminant A, 2 degree observer) of -3 to 3. However, it should also be noted that, for certain embodiments of the coated glass article 10, 10A, a non-neutral reflected and/or transmitted color may be desirable and can be exhibited. Also, the coated glass article 10, 10A may exhibit a low haze value. For example, the coated glass article 10, 10A may exhibit haze of 2.0% or less.

As discussed, above, the coating 20, 20A may be formed in conjunction with the manufacture of the glass substrate 18 in the well-known float glass manufacturing process. The float glass manufacturing process is typically carried out utilizing a float glass installation such as the installation 42 depicted in the FIG. 4. However, it should be understood that the float glass installation 42 described herein is only illustrative of such installations.

As illustrated in the FIG. 4, the float glass installation 42 may comprise a canal section 44 along which molten glass 46 is delivered from a melting furnace, to a float bath section 48 wherein the glass substrate is formed. In this embodiment, the glass substrate will be referred to as a glass ribbon 50. The glass ribbon 50 is a preferable substrate on which the coating 20, 20A is deposited. However, it should be appreciated that the glass substrate is not limited to being a glass ribbon.

The glass ribbon 50 advances from the bath section 48 through an adjacent annealing lehr 52 and a cooling section 54. The float bath section 48 includes: a bottom section 56 within which a bath of molten tin 58 is contained, a roof 60, opposite side walls (not depicted), and end walls 62, 64. The roof 60, side walls, and end walls 62, 64 together define an enclosure 66 in which a non-oxidizing atmosphere is maintained to prevent oxidation of the molten tin 58.

In operation, the molten glass 46 flows along the canal 44 beneath a regulating tweel 68 and downwardly onto the surface of the tin bath 58 in controlled amounts. On the molten tin surface, the molten glass 46 spreads laterally under the influence of gravity and surface tension, as well as certain mechanical influences, and it is advanced across the tin bath 58 to form the glass ribbon 50. The glass ribbon 50 is removed from the bath section 48 over lift out rolls 70 and is thereafter conveyed through the annealing lehr 52 and the cooling section 54 on aligned rolls. The deposition of the coating 20, 20A preferably takes place in the float bath section 48, although it may be possible for deposition to take place further along the glass production line, for example, in the gap 72 between the float bath 48 and the annealing lehr 52, or in the annealing lehr 52. Also, as illustrated in the FIG. 4, a plurality of coating apparatuses 74 are shown within the float bath section 48. As illustrated in FIG. 4, four coating apparatuses are provided. It is preferred that each layer of the coating 20, 20A is formed utilizing a separate coating apparatus. Thus, when forming the coated glass article 10A illustrated in FIG. 2, which has a coating 20A comprising or consisting of five coating layers, a fifth coating apparatus (not depicted in FIG 4) is preferably provided.

A suitable non-oxidizing atmosphere, generally nitrogen or a mixture of nitrogen and hydrogen in which nitrogen predominates, is maintained in the float bath section 48 to prevent oxidation of the molten tin 58 comprising the float bath. The glass ribbon is surrounded by float bath atmosphere. The atmosphere gas is admitted through conduits 76 operably coupled to a distribution manifold 78. The non-oxidizing gas is introduced at a rate sufficient to compensate for normal losses and maintain a slight positive pressure, on the order of between about 0.001 and about 0.01 atmosphere above ambient atmospheric pressure, so as to prevent infiltration of outside atmosphere. For purposes of the describing the invention, the above-noted pressure range is considered to constitute normal atmospheric pressure. The coating 20, 20A is preferably formed at essentially atmospheric pressure. Thus, the pressure of the float bath section 48, annealing lehr 52, and/or in the gap 72 between the float bath 48 and the annealing lehr 52 may be essentially atmospheric pressure. Heat for maintaining the desired temperature regime in the float bath section 48 and the enclosure 66 is provided by radiant heaters 80 within the enclosure 66. The atmosphere within the lehr 52 is typically atmospheric air, as the cooling section 54 is not enclosed and the glass ribbon 50 is therefore open to the ambient atmosphere. The glass ribbon 50 is subsequently allowed to cool to ambient temperature. To cool the glass ribbon 50, ambient air may be directed against the glass ribbon 50 as by fans 82 in the cooling section 54. Heaters (not depicted) may also be provided within the annealing lehr 52 for causing the temperature of the glass ribbon 50 to be gradually reduced in accordance with a predetermined regime as it is conveyed therethrough.

EXAMPLES

The following examples are presented solely for the purpose of further illustrating and disclosing the embodiments of the coated glass article. Examples of the coated glass article within the scope of the invention are described below and illustrated in TABLE 1 and TABLE 2.

In TABLE 1 , the coated glass articles within the scope of the invention are Ex 1 - Ex 6. A comparative example, not considered to be a part of the invention, is also described below and illustrated in TABLE 1 . In TABLE 1 , the comparative example is designated as C1. The comparative example of C1 was a sheet of glass sold under the trademark Pilkington Galaxsee and sold by Pilkington. The sheet of glass of C1 was of a thickness of 4 mm.

The coated glass articles of Ex 1 - Ex 6 are predictive. Each of the coated glass articles of Ex 1 - Ex 6 comprised a glass substrate. The glass substrates of Ex 1 - Ex 6 were each of a soda-lime-silica composition and a thickness of 4 mm. For Ex 1 and Ex 2, each glass substrate was a sheet of glass sold under the trademark Pilkington Optifloat Grey and sold by Pilkington. For Ex 3 and Ex 4, each glass substrate was a sheet of glass sold under the trademark Pilkington Optifloat Graphite Blue and sold by Pilkington. For Ex 5 and Ex 6, each glass substrate was a sheet of glass sold under the trademark Pilkington Galaxsee and sold by Pilkington.

Each of the coated glass articles of Ex 1 - Ex 6 also comprised a coating formed on a major surface of the glass substrate. The coatings of Ex 1 , Ex 3, and Ex 5 comprised a first coating layer, second coating layer, third coating layer, and fourth coating layer. The coatings of Ex 2, Ex 4, and Ex 6 comprised a first coating layer, second coating layer, third coating layer, fourth coating layer, and fifth coating layer.

For the coated glass articles of Ex 1 , Ex 3, and Ex 5, the fourth coating layer was deposited on the glass substrate and comprised tin oxide. The thickness of the fourth coating layer was 25 nm. The third coating layer was deposited on the fourth coating layer and comprised silicon dioxide. The thickness of the third coating layer was 25 nm. The second coating layer was deposited on the third coating layer and comprised antimony doped tin oxide. For the coated glass articles of Ex 1 , Ex 3, and Ex 5, the molar ratio of antimony to tin in the third coating layer was 0.08 - 0.14. The thickness of the second coating layer was 320 nm. The first coating layer was deposited on the second coating layer and comprised fluorine doped tin oxide. The thickness of the first coating layer was 220 nm.

For the coated glass articles of Ex 2, Ex 4, and Ex 6, the fifth coating layer was deposited on the glass substrate and comprised silicon dioxide. The thickness of the fifth coating layer was 25 nm. The fourth coating layer was deposited on the fifth coating layer and comprised antimony doped tin oxide. For the coated glass articles of Ex 2, Ex 4, and Ex 6, the molar ratio of antimony to tin in the fourth coating layer was 0.08 - 0.14. The thickness of the fourth coating layer was 125 nm. The third coating layer was deposited on the fourth coating layer and comprised silicon dioxide. The thickness of the third coating layer was 25 nm. The second coating layer was deposited on the third coating layer and comprised antimony doped tin oxide. For the coated glass articles of Ex 2, Ex 4, and Ex 6, the molar ratio of antimony to tin in the second coating layer was 0.08 - 0.14. The thickness of the second coating layer was 180 nm. The first coating layer was deposited on the second coating layer and comprised fluorine doped tin oxide. The thickness of the first coating layer was 220 nm.

Thus, the coated glass articles of Ex 1 , Ex 3, and Ex 5 are of a glass/Sn0₂/Si0₂/

Sn0₂:Sb/Sn0₂:F arrangement and the coated glass articles of Ex 2, Ex 4, and Ex6 are of a glass/Si0₂/Sn0₂:Sb/Si0₂/Sn0₂:Sb/Sn0₂:F arrangement. The total visible light transmittance (Tvis), transmitted color (Ta^*, Tb^*), coated side visible light reflectance (Rf), coated side reflected color (Rfa^*, Rfb^*), uncoated side reflected color (Rga^*, Rgb^*), U-value, solar heat gain coefficient (SHGC), and the direct solar energy transmittance (Tsol) of the coated glass articles of Ex 1 - Ex 6 and the sheet of glass of C1 are reported in TABLE 1. For the coated glass articles of Ex 1 - Ex 6, the total visible light reflectance, transmitted color, total visible light transmittance, reflected color, U-value, solar heat gain coefficient, and direct solar energy transmittance were calculated by optical modeling and according to the CIELAB color scale system using illuminant A, 2 degree observer.

For the coated glass articles of Ex 1 - Ex 6, the visible light reflectance is reported for the coated side of the coated glass article. The visible light reflectance refers to the percentage of visible light reflected from the coated glass article as measured from the side of the article that faces the coating. The reflected color is reported for both the coated side and uncoated side of the coated glass articles of Ex 1 - Ex 6. The total visible light transmittance is also reported below. The total visible light transmittance refers to the percentage of visible light passing through the article as measured from the side facing the coating. The total visible light reflectance and the total visible light transmittance are expressed as percentages. Also, the direct solar energy transmittance reported below is expressed as a percentage. TABLE 1

As shown in TABLE 1 , the coated glass articles of Ex 1 - Ex 6 exhibit an improved U- value and SHGC when compared to the glass sheet of C1 . For example, the coated glass articles of Ex 1 - Ex 6 exhibited a lower U-value than the U-value exhibited by the glass sheet of C1 . For example, the coated glass articles of Ex 1 - Ex 6 each exhibited a U-value of 0.5 versus a U-value of 0.93 which was exhibited by C1 . Therefore, the heat gain or loss through the coated glass articles of Ex 1 - Ex 6 due to environmental differences between the air on the sides of the articles will be less than the heat gain or loss through the glass sheet of C1. Additionally, the coated glass articles of Ex 1 and Ex 2 exhibited an SHGC that is more than 0.1 lower than the SHGC exhibited by the glass sheet of C1 . Thus, in the summer, if one of the coated glass articles of Ex 1 - Ex 6 is utilized in a window for a vehicle, the coated glass article will help to prevent the vehicle's passenger cabin from overheating. It should also be noted that the coated glass articles of Ex 1 - Ex 2 exhibited a direct solar energy transmittance of less than 15% and the coated glass articles of Ex 5 - Ex 6 exhibited a direct solar energy transmittance of less than 5%.

Furthermore, the coated glass articles of Ex 1 - Ex 6 each should exhibit an emissivity of 0.15 - 0.16. Thus, in the winter, if one of the coated glass articles of Ex 1 - Ex 6 is utilized in a window for a vehicle, the coated glass articles of Ex 1 - Ex 6 will provide an insulating effect for the vehicle's passenger cabin. The coated glass articles of Ex 1 - Ex 6 also exhibited other properties which are advantageous. For example, the coated glass articles of Ex 1 , Ex 3, Ex 5, and Ex6 each exhibited a neutral color in the visible light reflected from their uncoated side. Also, the coated glass articles of Ex 5 and Ex 6 each exhibited a neutral color in the visible light transmitted through each article. Additionally, the coated glass article of Ex 2 had a haze value that was less than the haze value exhibited by the coated glass article of Ex 1 .

In TABLE 2, the coated glass articles within the scope of the invention are Ex 7 and Ex 8. A comparative example, not considered to be a part of the invention, is also described below and illustrated in TABLE 2. In TABLE 2, the comparative example is designated as C2. The comparative example of C2 was a sheet of glass sold under the trademark Pilkington Galaxsee and sold by Pilkington. The sheet of glass of C2 was of a thickness of 4 mm.

The coated glass articles of Ex 7 and Ex 8 were formed using a float glass manufacturing process like the one described above. Each of the coated glass articles of Ex 7 and Ex 8 comprised a glass substrate. For Ex 7, the glass substrate had a soda-lime-silica composition, thickness of 4 mm, and was a sheet of glass sold under the trademark Pilkington Optifloat Grey and sold by Pilkington. For Ex 8, the glass substrate had a soda-lime-silica composition, thickness of 4.85 mm, and was a sheet of glass sold under the trademark Pilkington EZ-KOOL and sold by Pilkington.

Each of the coated glass articles of Ex 7 and Ex 8 also comprised a coating formed on a major surface of the glass substrate. The coatings of Ex 7 and Ex 8 comprised a first coating layer, second coating layer, third coating layer, fourth coating layer, and fifth coating layer.

For the coated glass articles of Ex 7 and Ex 8, the fifth coating layer was deposited on the glass substrate and comprised silicon dioxide. The thickness of the fifth coating layer was about 20 nm. The fourth coating layer was deposited on the fifth coating layer and comprised antimony doped tin oxide. For the coated glass articles of Ex 7 and Ex 8, the molar ratio of antimony to tin in the fourth coating layer was 0.08 - 0.14. The thickness of the fourth coating layer was about 100 nm. The third coating layer was deposited on the fourth coating layer and comprised silicon dioxide. The thickness of the third coating layer was about 25 nm. The second coating layer is deposited on the third coating layer and comprised antimony doped tin oxide. For the coated glass articles of Ex 7 and Ex 8, the molar ratio of antimony to tin in the second coating layer was 0.08 - 0.14. The thickness of the second coating layer was about 200 nm. The first coating layer was deposited on the second coating layer and comprised fluorine doped tin oxide. The thickness of the first coating layer was about 200 nm.

Thus, the coated glass articles of Ex 7 and Ex 8 were of a

glass/Si0₂/Sn0₂:Sb/Si0₂/Sn0₂:Sb/Sn0₂:F arrangement.

The total visible light transmittance (Tvis), transmitted color (Ta^*, Tb^*), coated side visible light reflectance (Rf), direct solar energy transmittance (Tsol), emissivity (ε), and the total solar heat transmittance (TSHT) of the coated glass articles of Ex 7 and Ex 8 and the sheet of glass of C2 are reported in TABLE 2. The total visible light transmittance, transmitted color, and visible light reflectance were measured on the coated side of the coated glass article using a

spectrophotometer according to CIELAB color scale system using illuminant A, 2 degree observer. The total visible light transmittance and total visible light reflectance are expressed as percentages. The direct solar energy transmittance is expressed as a percentage and was measured using a spectrophotometer. The emissivity was measured using an FTIR

spectrophotometer and the total solar heat transmittance was calculated using spectral data.

TABLE 2

As shown in TABLE 2, the coated glass articles of Ex 7 and Ex 8 exhibit an improved emissivity and TSHT when compared to the glass sheet of C2. For example, the coated glass articles of Ex 7 and Ex 8 exhibited a lower emissivity than the emissivity exhibited by the glass sheet of C2. For example, the coated glass articles of Ex 7 and Ex 8 each exhibited an emissivity of less than 0.2 versus an emissivity of 0.84 which was exhibited by C2. Therefore, in the winter, if one of the coated glass articles of Ex 7 and Ex 8 is utilized in a window for a vehicle, the coated glass article will provide an insulating effect for the vehicle's passenger cabin and help to prevent heat loss through the article from the passenger cabin to the exterior of the vehicle. Additionally, the coated glass articles of Ex 1 and Ex 2 exhibited a TSHT that is more than 7 lower than the THST exhibited by the glass sheet of C2. Thus, in the summer, if one of the coated glass articles of Ex 7 and Ex 8 is utilized in a window for a vehicle, the coated glass article will help to prevent the vehicle's passenger cabin from overheating. It should also be noted that the coated glass articles of Ex 7 and Ex 8 exhibited a direct solar energy transmittance of less than 25% and, more preferably, less than 20%. Also, similar to the glass sheet of C2, the coated glass article of Ex 7 exhibited a neutral color in the visible light transmitted through the article.

In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiments. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.

Claims

1 . A coated glass article, comprising:

a glass substrate; and

a coating formed on the glass substrate, wherein the coating comprises:

i. a first inorganic metal oxide layer deposited over a major surface of the glass substrate, wherein the first inorganic metal oxide layer comprises fluorine doped tin oxide,

ii. a second inorganic metal oxide layer deposited between the first inorganic metal oxide layer and the glass substrate, wherein the second inorganic metal oxide layer comprises antimony doped tin oxide,

wherein the coated glass article exhibits a visible light transmittance (llluminant A, 2 degree observer) of 35% or less.

2. The coated glass article of claim 1 , wherein the coated glass article exhibits a direct solar energy transmittance of less than 25%.

3. The coated glass article of claim 1 , wherein the second inorganic metal oxide layer has a thickness of 200 - 400 nm.

4. The coated glass article of claim 1 , further comprising a third inorganic metal oxide layer, wherein the third inorganic metal oxide layer separates the second inorganic metal oxide layer from a fourth inorganic metal oxide layer, the fourth inorganic metal oxide layer comprising antimony doped tin oxide.

5. The coated glass article of claim 1 , further comprising a third inorganic metal oxide layer, wherein the third inorganic metal oxide layer comprises silicon dioxide and separates the second inorganic metal oxide layer from a fourth inorganic metal oxide layer, the fourth inorganic metal oxide layer comprising tin oxide and being deposited directly on the major surface of the glass substrate.

6. The coated glass article of claim 1 , wherein the glass substrate is of a grey, grey- blue, blue-green, or green color.

7. The coated glass article of claim 2, wherein the coated glass article exhibits a direct solar energy transmittance of 20% or less.

8. The coated glass article of claim 3, wherein the second inorganic metal oxide layer has a thickness of 250 - 400 nm.

9. The coated glass article of claim 4, wherein the third inorganic metal oxide layer comprises silicon dioxide and has a thickness of 15 - 60 nm.

10. The coated glass article of claim 4, wherein the fourth inorganic metal oxide layer has a thickness of 100 - 150 nm.

11 . The coated glass article of claim 4, further comprising a fifth inorganic metal oxide layer, wherein the fifth inorganic metal oxide layer comprises silicon dioxide and is deposited between the fourth inorganic metal oxide layer and the glass substrate at a thickness of 15 - 60 nm.

12. The coated glass article of claim 4, wherein the second inorganic metal oxide layer and fourth inorganic metal oxide layer each have a molar ratio of antimony to tin of 0.08 - 0.14.

13. The coated glass article of claim 6, wherein the glass substrate is grey colored and the coated glass article exhibits a U-value of 0.60 or less, a TSHT of 35 or less, and the visible light transmitted through the coated glass article has an a^* value in the range of -6 to 6 and a b^* value in the range of -6 to 6 in the CIELAB color scale system (llluminant A, 2 degree observer).

14. A coated glass article, comprising:

a glass substrate; and

a coating formed on the glass substrate, wherein the coating comprises:

iii. a third inorganic metal oxide layer deposited between the second inorganic metal oxide layer and the glass substrate,

iv. a fourth inorganic metal oxide layer deposited between the third inorganic metal oxide layer and the glass substrate, wherein the fourth inorganic metal oxide layer comprises antimony doped tin oxide,

v. a fifth inorganic metal oxide layer deposited between the fourth inorganic metal oxide layer and the glass substrate, wherein the fifth inorganic metal oxide layer comprises silicon dioxide and is deposited at a thickness of 15 - 60 nm,

wherein the coated glass article exhibits a visible light transmittance (llluminant A, 2 degree observer) of 35% or less and a direct solar energy transmittance of 25% or less.

15. The coated glass article of claim 14, wherein the glass substrate is of a grey, grey- blue, or green color and the fifth inorganic metal oxide layer is deposited directly on the glass substrate.

16. A window for a vehicle comprising a coated glass article according to claim 1 or claim 14.