Low-e coated glass with neutral colours and high external reflectance value

Abstract

The invention is related to a low-e coated (20) glass (10) for use in architectural and automotive glazing, comprising at least one infrared reflective layer (23) with a single glass daylight transmittance value between 40 - 55% and a high external reflectance value and neutral colours.

Description

[0001] LOW-E COATED GLASS WITH NEUTRAL COLOURS AND HIGH EXTERNAL REFLECTANCE VALUE

[0002] TECHNICAL FIELD

[0003] The invention relates to a low-e coated glass which effectively transmits visible light while also providing heat control.

[0004] PRIOR ART

[0005] One of the factors that differentiate the optical properties of glasses is the coating applications made on the glass surface. One of the coating applications is the magnetic field-assisted sputtering method in a vacuum environment. This method is a frequently used method in the production of architectural and automotive coatings with low-e properties. The transmittance and reflectance values of the glasses coated with said method in the visible, near-infrared and infrared regions can be obtained at the targeted levels.

[0006] Apart from the visible region transmittance and reflectance values, the total solar energy transmittance (g) value is also an important parameter in coated glasses which can be used in the architectural and automotive sectors. The high total solar energy transmittance (g) value of the coatings can be preferred to in regards to reducing the heating loads in cold climate geographies. The total solar energy transmittance (g) values of the coatings can also be kept at the targeted levels by the number of Ag layers they contain, the type of nucleating layer used, and the parametric optimizations of the layers.

[0007] As a result, all the above-mentioned problems have made it imperative to make an innovation in the relevant technical field. BRIEF DESCRIPTION OF THE INVENTION

[0008] The present invention relates to a low-e-coated glass configuration with medium transmittance in order to eliminate the above-mentioned disadvantages and to bring new advantages to the relevant technical field.

[0009] The main object of the invention is to introduce a low-e coated glass with a medium transmittance value.

[0010] Another object of the invention is to introduce a low-e coated glass with reduced angular colour variation.

[0011] Another object of the invention is to introduce a low-e coated glass with reduced emissivity value.

[0012] Another object of the invention is to provide a heat treatable low-e coated glass.

[0013] In order to achieve all of the aforementioned objects and those which will arise from the detailed description below, the present invention is a low-e coated glass for use in architectural and automotive glazing, comprising at least one infrared reflective layer with a single glass daylight transmittance value between 45 - 55% and a high external reflectance value and neutral colours. Accordingly, said invention is characterized in that the thicknesses of a first dielectric structure positioned under and in contact with said infrared reflective layer and a second dielectric structure positioned above said infrared reflective layer are equal at a tolerance level of ±3 nm to ensure that the angular colour change in external reflectance remains constant up to 60°, and the ratio of the thickness of the infrared reflective layer to the sum of the thicknesses of the first barrier layer and the second barrier layer is at least 3 to ensure that the selectivity value is between 1.3 and 1.7.

[0014] A preferred embodiment of the invention is that the low-e coating optionally comprises a protective layer. A preferred embodiment of the invention is that the thickness of said protective layer is less than the thickness of each of the total thickness of the first dielectric structure and the total thickness of the second dielectric structure.

[0015] In a preferred embodiment of the invention, the ratio of the thickness of the second barrier layer to the thickness of the first barrier layer is between 1.8 and 2.2.

[0016] In a preferred embodiment of the invention, said first dielectric structure comprises a first dielectric layer in contact with the glass and comprising Si.

[0017] Another preferred embodiment of the invention is that said protective layer comprises Si and is in contact with the second dielectric structure.

[0018] Another preferred embodiment of the invention is that the low-e coating configuration has a symmetrical arrangement of layers when progressing from the infrared reflective layer toward the glass on one side and toward the air on the other side.

[0019] BRIEF DESCRIPTION OF THE DRAWING

[0020] Figure 1 shows a representative embodiment of the low-e coated glass.

[0021] REFERENCE NUMERALS GIVEN IN THE DRAWING

[0022] 10 Glass

[0023] 20 Low-e coating

[0024] 21 First dielectric structure

[0025] 211 First dielectric layer

[0026] 212 Second dielectric layer

[0027] 22 First barrier layer

[0028] 23 Infrared reflective layer

[0029] 24 Second barrier layer

[0030] 25 Second dielectric structure

[0031] 251 Third dielectric layer

[0032] 252 Fourth dielectric layer

[0033] 26 Protective layer DETAILED DESCRIPTION OF THE INVENTION

[0034] In this detailed description, the low-e coated (20) glass (10) subject to the invention is explained by way of example only for a better understanding of the subject which will not create any limiting effect.

[0035] The production of low-e coated (20) glass (10) for architecture and automotive is carried out by the sputtering method. This invention generally relates to single silver low-e coated (20) glasses (10) with high heat treatment resistance, which are used as daylight transmitting and heat insulating glass (10), and the contents and application of said low-e coating (20). The low-e coated (20) glass (10) subject to the invention can be used in double glazing units and laminated structures in the architectural and automotive sectors.

[0036] In this invention, in order to obtain a low-e coated (20) glass (10) which has a medium level of visible light transmittance for application on the surface of a glass (10), is heat treatable and is designed such that the angular colour change is at a level showing minimal change, by using the sputtering method, a low-e coating (20) consisting of multiple metal, metal oxide and metal nitride / oxynitride layers located on the glass (10) surface has been developed. Said layers are deposited on top of each other in a vacuum environment. At least one and / or more of the tempering, partial tempering, annealing, lamination and bending processes can be used together as heat treatment. The low-e coated (20) glass (10) subject to the invention can be used as architectural and automotive glass (10).

[0037] The term optical performance mentioned in the invention refers to the solar energy transmittance, visible region light transmittance, internal and external reflectance values, L*-a*-b* colour values of the low-e coated (20) glass (10).

[0038] The refractive indices of all layers in the low-e coated (20) glass (10) subject to the invention were determined using computational methods based on the optical constants obtained from single layer measurements. Said refractive indices are the refractive index data at 550 nm. As a result of experimental studies to develop a low-e coating (20) arrangement that is preferred both in terms of ease of production and optical properties, the following data were determined.

[0039] The low-e coating (20) subject of the invention comprises an infrared reflective layer (23) that allows to transmit the solar energy spectrum visible region (hereinafter referred to as % TVjS) at a targeted level and to reflect (by transmitting less) thermal radiation in the infrared region. Ag layer is used as the infrared reflective layer (23) and heat radiation is low.

[0040] In the low-e coating (20) subject to the invention, a first dielectric structure (21) is used in contact with the glass (10). Said first dielectric structure (21) comprises at least one or more of the materials SixNy, SiOxNy, ZnAI, ZnAIOxZnSnOx, TiOx, TiNx, ZrNx. In the preferred embodiment, the first dielectric structure (21) comprises a first dielectric layer (211) and a second dielectric layer (212) in contact with each other.

[0041] Said first dielectric layer (211) comprises at least one of the materials SixNy, SiOxNy, ZnAI, ZnAIOx ZnSnOx, TiOx, TiNx, ZrNx. In the preferred embodiment, the first dielectric layer (211) has a structure that contains Si. In an embodiment of the invention, the first dielectric layer (211) comprises SixNy. The first dielectric layer (211) comprising SixNyacts as a diffusion barrier, inhibiting alkaline ion migration which is facilitated at high temperature. Thus, the first dielectric layer (211) comprising SixNysupports the resistance of the low-e coating (20) to heat treatment processes. The range of variation for the refractive index of the first dielectric layer (211) comprising SixNyis between 2.00 and 2.15. The range of variation for the refractive index of the first dielectric layer (211) comprising SixNyin the preferred structure is 2.02 to 2.12.

[0042] Said second dielectric layer (212) comprises at least one of the materials SixNy, SiOxNy, ZnAI, ZnAIOx ZnSnOx, TiOx, TiNx, ZrNx. In the preferred embodiment the second dielectric layer (212) comprises ZnAIOx. The range of variation for the refractive index of the second dielectric layer (212) comprising ZnAIOxis between 2.0 and 2.15. The range of variation for the refractive index of the second dielectric layer (212) comprising ZnAIOxin the preferred structure is 2.0 to 2.12. The thickness of the first dielectric layer (211) comprising SixNyis between 12 nm - 30 nm. In the preferred embodiment, the thickness of the first dielectric layer (211) comprising SixNyis between 15 nm - 27 nm. In a more preferred embodiment, the thickness of the first dielectric layer (211) comprising SixNyis between 18 nm - 24 nm. The first dielectric layer (211) comprising SixNybeing at the specified thicknesses allows the low-e coated (20) glass (10) to be more resistant to tempering. If the first dielectric layer (211) comprising SixNyin contact with the glass (10) is thinner than the specified thickness values, the low-e coating (20) may deteriorate during tempering.

[0043] The second dielectric layer (212) comprising ZnAIOxis located on the first dielectric layer (211). The thickness of the second dielectric layer (212) comprising ZnAIOxis between 8 nm - 24 nm. In the preferred embodiment the thickness of the second dielectric layer (212) comprising ZnAIOxis between 11 nm - 21 nm. In a more preferred embodiment the thickness of the second dielectric layer (212) comprising ZnAIOxis between 14 nm - 18 nm.

[0044] The first barrier layer (22) is positioned above and in contact with the second dielectric layer (212) comprising ZnAIOx. At least one of NiCr, NiCrOx, Ti, TiOx, ZnAIOx, ZnOxis used as the first barrier layer. In the preferred embodiment, one of NiCr or NiCrOxis used. The thickness of the first barrier layer (22) is between 1 nm - 10 nm. In the preferred embodiment, the thickness of the first barrier layer (22) is between 1 nm - 7 nm. In a more preferred embodiment, the thickness of the first barrier layer (22) is between 1 nm - 4 nm.

[0045] An infrared reflective layer (23) is located above and in contact with the first barrier layer (22). Ag layer is used as the infrared reflective layer (23). The thickness of said infrared reflective layer (23) is in the range of 10 nm - 22 nm. In the preferred embodiment, the thickness of the infrared reflective layer (23) is in the range of 12 nm - 20 nm. Most preferably, the thickness of the infrared reflective layer (23) is in the range of 14 nm - 18 nm.

[0046] A second barrier layer (24) is positioned above and in contact with the infrared reflective layer (23). At least one of NiCr, NiCrOx, TiOx, ZnSnOx, ZnAIOx, ZnOxis used as the barrier layer (24). In the preferred embodiment, the barrier layer (24) comprises one of either NiCr or NiCrOx. In an embodiment of the invention, NiCr is used as the barrier layer (24). In another alternative embodiment of the invention, NiCrOxis used as the barrier layer (24). The thickness of the second barrier layer (24) is in the range of 1 nm - 9 nm. In the preferred embodiment, the thickness of the second barrier layer (24) is in the range of 1.5 nm - 7 nm. Most preferably, the thickness of the second barrier layer (24) is in the range of 2 nm - 5 nm.

[0047] In an embodiment of the invention, the first barrier layer (22) and the second barrier layer (24) are preferably of metallic structure. The total thickness of the first barrier layer (22) and the second barrier layer (24) is between 3 nm and 8 nm to achieve the targeted performance. In the preferred embodiment, the total thickness of the first barrier layer (22) and the second barrier layer (24) is between 3 nm and 6 nm to achieve the targeted performance.

[0048] It is also preferred that the ratio of the thickness of the infrared reflective layer (23) to the total thickness of the first barrier layer (22) and the second barrier layer (24) is at least 3. In this way, the selectivity value of low-e coated (20) glass (10) can be kept between 1.3 and 1.7. In addition, thanks to this ratio, the transmittance of low-e coated (20) glass (10) is at least 40%.

[0049] A second dielectric layer (25) is positioned above and in contact with the second barrier layer (24). Second dielectric layer (25) comprises at least three of the materials SixNy, SiOxNy, ZnSnOx, ZnAIOx, TiZrOx, TiOx, TiNx, ZrNx. The second dielectric structure (25) comprises a third dielectric layer (251) and a fourth dielectric layer (252) in contact with each other, respectively.

[0050] Third dielectric layer (251) comprises at least one of the materials SixNy, SiOxNy, ZnSnOx, ZnAIOx, TiZrOx, TiOx, TiNx, ZrNx. In the preferred embodiment, ZnAIOx is used as the third dielectric layer (251). The thickness of the third dielectric layer (251) is in the range of 10 nm - 27 nm. In the preferred embodiment, the thickness of the third dielectric layer (251) is in the range of 13 nm - 24 nm. Most preferably, the thickness of the third dielectric layer (251) is in the range of 15 nm - 21 nm.

[0051] Fourth dielectric layer (252) comprises at least one of the materials SixNy, SiOxNy, ZnSnOx, ZnAIOx, TiZrOx, TiOx, TiNx, ZrNx. In the preferred embodiment, SixNy is used as the fourth dielectric layer (252). The thickness of the fourth dielectric layer (252) is in the range of 8 nm - 25 nm. In the preferred embodiment, the thickness of the fourth dielectric layer (252) is in the range of 11 nm - 22 nm. Most preferably, the thickness of the fourth dielectric layer (252) is in the range of 13 nm - 19 nm.

[0052] An optional protective layer (26) is positioned above and in contact with the second dielectric structure (25). The protective dielectric layer (26) comprises at least one of the materials SixNy, SiOxNy, ZnSnOx, ZnAIOx, TiZrOx, TiOx, TiNx, ZrNx. In the preferred embodiment, the protective layer (26) has a structure that contains Si. In an embodiment of the invention, SiOxNy is used as the protective layer (26). The thickness of the protective layer (26) is in the range of 14 nm - 32 nm. In the preferred embodiment, the thickness of the protective layer (26) is in the range of 17 nm - 29 nm. Most preferably, the thickness of the protective layer (26) is in the range of 20 nm - 26 nm.

[0053] The total thickness of the first dielectric structure (21) under the infrared reflective layer (23) in the low-e coating (20) subject to the invention is less than the total thickness of the second dielectric structure (25) above the infrared reflective layer (23). Thus, the colour values can be obtained at the desired levels from the optical performance values of the final product low-e coated (20) glass (10).

[0054] The total thickness of the first dielectric structure (21) is between 20 nm and 54 nm. In the preferred embodiment, the total thickness of the first dielectric structure (21) is between 23 nm and 51 nm. Most preferably, the total thickness of the first dielectric structure (21) is between 26 nm and 48 nm.

[0055] The total thickness of the second dielectric structure (25) is between 32 nm and 84 nm. In the preferred embodiment, the total thickness of the second dielectric structure (25) is between 35 nm and 81 nm. Most preferably, the total thickness of the second dielectric structure (25) is between 38 nm and 78 nm.

[0056] It is preferred that the low-e coated (20) glasses (10) subject to the invention have neutral external reflectance colour values in IGU. In order to achieve this, the layer arrangement and thicknesses in the low-e coating (20) were optimized to obtain a* values between (0.0) - (3.0) and b* values between (0.5) - (3.2) after heat treatment in single glass applications. In the preferred embodiment, the glass side reflectance a* value after heat treatment in single glass applications is between (0.3) - (2.5) and b* value is between (1.2) - (2.8). Most preferably, the glass side reflectance a* value after heat treatment in single glass applications is between (1.0) - (2.0) and the b* value is between (1.5) - (2.5).

[0057] The a* value obtained after IGU applications is between (-1.0) - (1.9) and the b* value is between (1.0) - (3.0). After IGU applications in the preferred embodiment, the a* value is between (-0.5) - (1.3) and the b* value is between (1.3) - (2.5). Most preferably, the a* value obtained after IGU applications is between (0.0) and (1.0) and the b* value is between (1.6) and (2.1).

[0058] The thickness of the first barrier layer (22) and the second barrier layer (24) has an impact on the reflectance values. The second barrier layer (24) is thicker than the first barrier layer (22), ensuring that internal reflectance is lower than external reflectance after heat treatment. In addition, the first barrier layer (22) and the second barrier layer (24) contribute to improving the mechanical properties of the low-e coated (20) glass (10). The internal reflectance value after single glass heat treatment is between 20% and 25%. External reflectance value after single glass heat treatment is between 30% and 35%. In IGU applications, on the other hand, the internal reflectance value after heat treatment is between 23% and 28% and the external reflectance value is between 33% and 38%.

[0059] The ratio of the thickness of the second barrier layer (24) to the thickness of the first barrier layer (22) in the low-e coating (20) is between 1.8 - 2.2. In this way, the emissivity value before heat treatment is kept in the range of 0.043 - 0.047 and the emissivity value after heat treatment is kept in the range of 0.030 - 0.035.

[0060] The single glass daylight transmittance value of the low-e coated (20) glass (10) subject to the invention after heat treatment is between 40 - 55%. In IGU applications, on the other hand, the daylight transmittance value after heat treatment is between 40- 50%. Preferably, in IGU applications, the daylight transmittance value of low-e coated (20) glass (10) after heat treatment is 43%.

[0061] In a preferred embodiment of the invention, it is as follows: Glass / SixNy / ZnAIOx / NiCrOx / Ag / NiCrOx / ZnAIOx / SixNy / SiOxNy. In another preferred embodiment of the invention, the structure is as follows: Glass / SiOxNy / ZnAIOx / NiCrOx / Ag / NiCrOx / ZnAIOx / SixNy / SiOxNy.

[0062] In another preferred embodiment of the invention, the structure is as follows: Glass / SiOxNy / ZnAIOx / NiCrOx / Ag / NiCrOx / ZnAIOx / SixNy / SixNy.

[0063] In another preferred embodiment of the invention, the structure is as follows: Glass / SixNy / ZnAIOx / NiCrOx / Ag / NiCrOx / ZnAIOx / SixNy / SixNy.

[0064] In another preferred embodiment of the invention, the structure is as follows: Glass / SixNy / ZnAIOx / NiCr / Ag / NiCr / ZnAIOx / SixNy / SiOxNy.

[0065] In another preferred embodiment of the invention, the structure is as follows: Glass / SiOxNy / ZnAIOx / NiCr / Ag / NiCr / ZnAIOx / SixNy / SiOxNy.

[0066] In another preferred embodiment of the invention, the structure is as follows: Glass / SiOxNy / ZnAIOx / NiCrx / Ag / NiCr / ZnAIOx / SixNy / SixNy.

[0067] In another preferred embodiment of the invention, the structure is as follows: Glass / SixNy / ZnAIOx / NiCr / Ag / NiCr / ZnAIOx / SixNy / SixNy.

[0068] In another preferred embodiment of the invention, the structure is as follows: Glass / SixNy / ZnAIOx / NiCr / Ag / NiCrOx / ZnAIOx / SixNy / SiOxNy.

[0069] In another preferred embodiment of the invention, the structure is as follows: Glass / SiOxNy / ZnAIOx / NiCr / Ag / NiCrOx / ZnAIOx / SixNy / SiOxNy.

[0070] In another preferred embodiment of the invention, the structure is as follows: Glass / SiOxNy / ZnAIOx / NiCrOx / Ag / NiCr / ZnAIOx / SixNy / SixNy.

[0071] In another preferred embodiment of the invention, the structure is as follows: Glass / SixNy / ZnAIOx / / NiCrOxr / Ag / NiCr / ZnAIOx / SixNy / SixNy.

[0072] In order to achieve the targeted performance, the materials used in the layers positioned outwardly from the glass (10) are symmetrically arranged, except for the protective layer (26) in the low-e coating (20) configuration subject to the invention. Here, the dielectric layers are not only uniform in material content but also in thickness, with a manufacturing tolerance of ±3 nm. In the low-e coating (20) subject to the invention, the total layer thicknesses of the first dielectric structure (21) and the second dielectric structure (25) are equal with a manufacturing tolerance of ±3 nm. This ensures that the angular colour change remains constant up to 60 degrees. The thickness of the protective layer (26) is less than the total thickness of each of said first dielectric structure (21) and second dielectric structure (25). This contributes to keeping the colour values of low-e coated (20) glass (10) within the desired range.

[0073] The scope of protection of the invention is specified in the appended claims and cannot be limited to what is described for illustrative purposes in this detailed description. It is clear that a person skilled in the art can produce similar embodiments in the light of what is explained above, without deviating from the main theme of the invention.

Claims

CLAIMS1. A low-e coated (20) glass (10) for use in architectural and automotive glazing, comprising at least one infrared reflective layer (23) with a single glass daylight transmittance value between 40 - 55% and a high external reflectance value and neutral colours, characterised in that the thicknesses of a first dielectric structure (21) positioned under said infrared reflective layer (23) and a second dielectric structure (25) positioned above the infrared reflective layer (23) are equal at a tolerance level of ±3 nm to ensure that the angular colour change in external reflectance remains constant up to 60°, and the ratio of the thickness of the infrared reflective layer (23) to the sum of the thicknesses of the first barrier layer (22) and the second barrier layer (24) is at least 3 to ensure that the selectivity value is between 1.3 and 1.7.

2. A low-e coated (20) glass (10) according to claim 1 , characterised in that the low-e coating (20) optionally comprises a protective layer (26).

3. A low-e coated (20) glass (10) according to claim 2, characterised in that the thickness of said protective layer (26) is less than the thickness of each of the total thickness of the first dielectric structure (21) and the total thickness of the second dielectric structure (25).

4. A low-e coated (20) glass (10) according to claim 1, characterised in that the ratio of the thickness of the second barrier layer (24) to the thickness of the first barrier layer (22) is between 1.8 - 2.2.

5. A low-e coated (20) glass (10) according to claim 1 , characterised in that said first dielectric structure (21) comprises a first dielectric layer (211) in contact with the glass and comprising Si.

6. A low-e coated (20) glass (10) according to claim 2, characterised in that said protective layer (26) comprises Si and is in contact with the second dielectric structure (25).

7. A low-e coated (20) glass (10) according to claim 1 , characterised in that the low-e coating (20) configuration has a symmetrical arrangement of layers when progressing from the infrared reflective layer (23) toward the glass (10) on one side and toward the air on the other side.

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