Low-e coated glass with high visible transmittance

Abstract

The invention relates to a glass (10) with a low-E coating (20) with a high transmittance, which is suitable for use in architecture and automotive, characterized in that it comprises a lower dielectric structure (21), an Ag-containing first functional layer (22), a protective layer (23), a intermediate dielectric structure (24), an Ag-containing second functional layer (25), an upper dielectric structure (26), respectively, other than glass (10).

Description

[0001] LOW-E COATED GLASS WITH HIGH VISIBLE TRANSMITTANCE

[0002] TECHNICAL FIELD

[0003] The invention relates to a low-E coated glass with a high transmittance, which is suitable for use in architecture and automotive.

[0004] PRIOR ART

[0005] One of the factors that differentiate the optical properties of glasses is the coating applications on the glass surface. One of the coating applications is a magnetic field- assisted sputtering method in vacuum environment. This method is frequently used in the production of architectural and automotive coatings with the low-E property. 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] In addition to the visible region transmittance and reflectance values, the value of the total solar energy transmittance (g) is also an important parameter for coated glass that can be used in the architecture and automotive sector. With the value of the high total solar energy transmittance (g) of the coatings, it can be preferred to reduce the heating loads in the cold climate geographies. The values of the total solar energy transmittance (g) of the coatings can also be kept at the targeted levels with the number of Ag layers, the type of nucleating layer used, and parametric optimizations of the layers.

[0007] As a result, all the above-mentioned problems have made it necessary to realize a novelty in the relevant technical field.

[0008] SUMMARY OF THE INVENTION

[0009] The present invention relates to a low-E coated glass to eliminate the above-mentioned disadvantages and bring the new advantages to the relevant technical field.

[0010] An object of the invention is to provide a low-E coated glass with a high transmittance value. Another object of the invention is to provide a low-E coated glass in neutral tones.

[0011] A further object of the invention is to provide a low-E coated glass in which the dielectric optical paths are optimized to obtain a high transmittance product in a low-E configuration with multiple silver.

[0012] In order to accomplish all the objects mentioned above and to be revealed from the detailed description below, the present invention relates to a low-E coated glass with a high transmittance, which is suitable for use in architecture and automotive. Accordingly, the present invention is characterized in that other than glass, it comprises

[0013] - a lower dielectric structure,

[0014] - an Ag-containing first functional layer,

[0015] - a protective layer,

[0016] - an intermediate dielectric structure,

[0017] - an Ag-containing second functional layer,

[0018] - an upper dielectric structure, respectively, and the total optical path (designated with TDOT) of the upper dielectric structure is at most 82 nm, including this value, the total optical path (designated with BTOD) of the lower dielectric structure is at least 65 nm, including this value, and the sum of the total optical path (TDOT) of the upper dielectric structure and the total optical path (BTOD) of the lower dielectric structure is 0.84-0.94 times the value of the total optical path (designated with MDOT) of the intermediate dielectric structure.

[0019] In a preferred embodiment of the invention, the second functional layer is thicker than the first functional layer.

[0020] In another preferred embodiment of the invention, the intermediate dielectric structure comprises at least 3 layers of medium refractive index structured in a sandwich form, with the bottom and top having the same content.

[0021] In another preferred embodiment of the invention, the upper dielectric structure comprises a ZnAIOx layer positioned over and in contact with the second functional layer. In another preferred embodiment of the invention, said lower dielectric structure comprises at least one dielectric layer with a high refractive index and at least one layer with a medium refractive index.

[0022] In another preferred embodiment of the invention, the lower dielectric structure comprises preferably at least one dielectric layer with a high refractive index and at least two layers with a medium refractive index.

[0023] In another preferred embodiment of the invention, said upper dielectric structure comprises at least one layer with a medium refractive index.

[0024] In another preferred embodiment of the invention,

[0025] - the lower dielectric structure is in the thickness range of 25 nm - 45 nm

[0026] - the first functional layer is in the thickness range of 7 nm - 15 nm

[0027] - the protective layer is in the thickness range of 1 .5 nm- 6 nm

[0028] - the intermediate dielectric structure is in the thickness range of 70 nm - 95 nm

[0029] - the second functional layer is in the thickness range of 10 nm- 16 nm and the upper dielectric structure is in the thickness range of 32 nm- 50 nm.

[0030] BRIEF DESCRIPTION OF THE DRAWING

[0031] Fig. 1 shows a representative overview of a Low-E coated glass.

[0032] REFERENCE NUMBERS GIVEN IN THE DRAWING

[0033] 10 Glass

[0034] 20 Low-E coating

[0035] 21 Lower dielectric structure

[0036] 22 First functional layer

[0037] 23 Protective layer

[0038] 24 Intermediate dielectric structure

[0039] 25 Second functional layer

[0040] 26 Upper dielectric structure

[0041] DETAILED DESCRIPTION OF THE INVENTION In this detailed description, the glass (10) with low-E coating (20) according to the invention is only described with the examples without any limiting effect for a better understanding of the subject.

[0042] The glasses (10) with a low-E coating (20) for architecture and automotive is produced by sputtering method (known in the art). The present invention relates to the doublesilver glasses (10) with low-E coating (20) generally used as daylight transmitting and heat insulating glass (10), and the content and application of said low-E coating (20). The glass (10) with low-E coating (20) of the invention can be used in thermal glazing units and laminated structures for the architecture and automotive sectors.

[0043] In the present invention, a low-E coating (20) consisting of a plurality of metal, metal oxide and metal nitride / oxynitride layers positioned on the surface of the glass (10) has been developed by using the sputtering method in order to obtain a glass (10) with a low- E coating (20) having a high level of visible light transmittance for application on the surface of a glass (10) and designed in such a way that the angular color change is at a level to show the least change. These layers are deposited one on top of the other in a vacuum environment. The glass (10) with low-E coating (20) of the invention can be used as an architectural and automotive glass (10).

[0044] The term optical performance in the invention refers to the solar energy transmittance, visible region light transmittance, internal and external reflection values and color values of L a* b* of the glass (10) with low-E coating (20).

[0045] In the invention;

[0046] The term BDOT refers to the sum of the optical path of the lower dielectric structure.

[0047] The term MDOT refers to the sum of the optical path of the intermediate dielectric structure.

[0048] The term TDOT refers to the sum of the optical path of the upper dielectric structure.

[0049] The refractive indices of all layers in the glass (10) with low-E coating (20) of the invention were determined using computational methods based on the optical constants obtained from single layer measurements. These refractive indices are refractive index data at 550 nm. The refractive indices of the layers that make up the low-E coating (20) vary between 1 .5 and 2.6. In the invention, a refractive index value of 1 .7 and below is defined as low, while a refractive index value of 2.2 and above is defined as high. The values between 1 .7 and 2.2 are defined as medium refractive index values.

[0050] In order to develop a preferred low-E coating (20) arrangement in terms of both ease of production and optical properties, the following data were determined as a result of experimental studies.

[0051] The low-E coating (20) of the invention comprises a first functional layer (22) and a second functional layer (25) which provide a targeted level of transmittance in the visible region of the solar energy spectrum (hereinafter referred to as % TViS) and reflection (less transmittance) of thermal radiation in the infrared region. Ag layer is used as the first functional layer (22) and the second functional layer (25) and has a low heat dissipation.

[0052] In the low-E coating (20) of the invention, a lower dielectric structure (21 ) is used to contact the glass (10). Said lower dielectric structure (21 ) comprises at least one or more of the materials SixNy, SiOxNy, ZnAIOxZnSnOx, TiOx, TiNx, ZrNx, TiNbOx, NbZrOx, TiZrOx, NbNx. The lower dielectric structure (21 ) preferably comprises at least one dielectric layer with a high refractive index and at least one layer with a medium refractive index. In an alternative embodiment of the invention, the lower dielectric structure (21 ) comprises preferably at least one dielectric layer with a high refractive index and at least two layers with a medium refractive index. The total thickness of the lower dielectric structure (21 ) is between 25 nm- 45 nm. In the preferred embodiment, the total thickness of the lower dielectric structure (21 ) is between 30 nm - 41 nm.

[0053] The first functional layer (22) is located on the lower dielectric structure (21 ). The Ag layer is used as the first functional layer (22). The thickness of the first functional layer (22) is between 7 nm - 15 nm. In the preferred embodiment, the thickness of the first functional layer (22) is between 7.5 nm - 13 nm. Most preferably, the thickness of the first functional layer (22) is between 8.5 nm - 1 1 nm.

[0054] A protective layer (23) is positioned on the first functional layer (22). As the protective layer (23), at least one of NiCr, NiCrOx, Ti, TiOx, ZnSnOx, ZnAIOx, ZnOxis used. In the preferred embodiment, the protective layer (23) comprises one of NiCr or NiCrOx. In one embodiment of the invention, NiCr is used as the protective layer (23). In an alternative embodiment of the invention, NiCrOxis used as the protective layer (23). The thickness of the protective layer (23) is between 1 .5 nm - 6 nm. In the preferred embodiment, the thickness of the protective layer (23) is between 1 .7 nm - 4 nm. The protective layer (23) containing either NiCr or NiCrOx provides that the reflective property of the first functional layer (23) is maintained.

[0055] An intermediate dielectric structure (24) is located on the protective layer (23). The intermediate dielectric structure (24) comprises at least one of the materials SixNy, SiOxNy, ZnAIOx ZnSnOx, TiOx, TiNx, ZrNx, TiNbOx, NbZrOx, TiZrOx, NbNx. The intermediate dielectric structure (24) preferably comprises multiple layers with the medium refractive indices. In the preferred embodiment, the arrangement of the intermediate dielectric structure (24) is a sandwich structure. The sandwich configuration preferably consists of at least 3 layers. The same material is preferred for the layers located at the top and bottom of these at least 3 layers. Sandwich structures with more layers can also be used in the alternative applications. The total thickness of the intermediate dielectric structure (24) is between 70 nm- 95 nm. In the preferred embodiment, the total thickness of the intermediate dielectric structure (24) is between 77 nm- 90 nm.

[0056] The second functional layer (25) is located on the intermediate dielectric structure (24). The Ag layer is used as the second functional layer (25). The thickness of the second functional layer (25) is between 10 nm - 16 nm. In the preferred embodiment, the thickness of the second functional layer (25) is between 11 nm - 15 nm. In the most preferred embodiment, the thickness of the second functional layer (25) is between 12 nm - 14 nm.

[0057] An upper dielectric structure (26) is located on the second functional layer (25). The upper dielectric structure (26) comprises at least one or more of the materials SixNy, SiOxNy, ZnAIOx ZnSnOx, TiOx, TiNx, ZrNx, TiNbOx, NbZrOx, TiZrOx, NbNx. The upper dielectric structure (26) comprises at least one layer with the medium refractive index. In an alternative embodiment of the invention, the upper dielectric structure (26) comprises at least two layers with the medium refractive index. The total thickness of the upper dielectric structure (26) is between 32 nm- 50 nm. In the preferred embodiment, the total thickness of the upper dielectric structure (26) is between 36 nm- 46 nm. The thickness of the second functional layer (25) in the low-E coating (20) configuration is greater than that of the first functional layer (22). As is known in the art, the functional layers have a high impact on the optical transmittance values of the glass (10) with low- E coating (20). When measured as a single glass, the total thickness of the functional layers must be within a certain value range in order to obtain a visible region transmittance value in the range of 75-82%.

[0058] The sum of the thicknesses of the functional layers should not be below a certain thickness in order to achieve the targeted emissivity value. It is preferred that the thickness of the second functional layer (25) mentioned above is greater than the thickness of the first functional layer (22) in order to obtain the emissivity value at the desired level without sacrificing the optical transmittance.

[0059] At least one of the layers in the upper dielectric structure (26) is ZnAIOx. Said ZnAIOxis positioned on the second functional layer (25) in contact therewith to protect the second functional layer (25). In this way, the visible region transmittance level of a single glass (10) can be achieved between 75-82%. In addition, the use of ZnAIOx contributes to the lower emissivity value of the low-E coating (20) compared to the use of a different protective layer such as NiCr, NiCrOx, Ti, as the absorption of ZnAIOx at infrared wavelengths is slightly lower than that of the other protective layer (23).

[0060] The sum of BDOT and TDOT is 0.84 - 0.94 times that of MDOT, provided that the low-E coating (20) configuration of the invention is used as a protective layer of ZnAIOx positioned to contact the second functional layer (25). In addition, the TDOT value should be at most 82 nm and the BDOT value should be at least 65 nm.

[0061] (MDOT x 0.84) < BDOT+TDOT < (MDOT x 0.94)

[0062] With the combination of these conditions, the internal and external reflection characteristics of the glass (10) with low-E coating (20) are similar.

[0063] In the studies, MTOD values were kept constant in order to make comparative evaluations in the measurements. This is critical to achieve the targeted performance of the low-E coating (20) mentioned in the above equation. According to the studies conducted in this context, when we change the BTOD value while the TDOT is constant at the upper value and the BTOD value exceeds the upper limit within the scope of the above equation, the color performance values go out of neutral values (Examples 7-8). Similarly, when we change the TDOT value while the BTOD value is constant at the 5 targeted lower limit and the TDOT value exceeds the lower limit according to the above equation, the color performance values go out of neutral values (Examples 1 -2).

[0064] If the MDOT value remains constant and the BDOT and TDOT values decrease (Examples 1 -2), the reflection a* color values on the coated and uncoated side shift0 towards the negative values and the b* color values shift towards the positive values, i.e. the coating reflection color becomes yellowish green tones.

[0065] If the MDOT value remains constant and the BDOT and TDOT values are increased (Examples 7-8), the reflection a* color value on the coated and uncoated side shifts 5 towards the positive value and the b* color value shifts towards the negative value, i.e. the coating reflection color becomes dominant blue and purple tones.

[0066] The targeted performance values for the glass (10) with low-E coating (20) of the invention are targeted to be -3 (±3) for a* and b* values of both coated and uncoated0 side. Reflection values are also targeted to be 6.5 (±1 ) for the coated side and 7.5 (±1 ) for the uncoated side. Therefore, the constraints mentioned above are critical to ensure that the color tones (hue) does not deviate between the glasses (10) to which the low-E coating (20) is applied. If said MDOT value above remains constant and especially the BDOT values are reduced, the internal and external reflection values increase, while if 5 the MDOT value remains constant and especially the TDOT values are reduced, the internal and external reflection values decrease and the color tone changes. The results of the related studies are given in Table 1 .

[0067] Table 1 : Variations in optical performance in different optical path applications

[0068] Examples 3, 4, 5 and 6 of the studies given in Table 1 are related to the case where the desired conditions are met. The BDOT, TDOT and MTOD values are outside the lower and upper limits of the equation, 0.84 and 0.94, in the embodiments of examples 1 , 2, 7 5 and 8, and in this case the reflectance and color values are outside the target values.

[0069] The scope of protection of the invention is described in the attached claims and cannot be limited to what is explained in this detailed description for the exemplary purposes. It is clear that a person skilled in the art can produce similar embodiments in the light of0 what is explained above, without deviating from the main theme of the invention.

Claims

CLAIMS1 . A glass (10) with a low-E coating (20) with a high transmittance, which is suitable for use in architecture and automotive, characterized in that it comprises the following sequence outwardly from the glass (10), respectively:- a lower dielectric structure (21 ),- an Ag-containing first functional layer (22),- a protective layer (23),- an intermediate dielectric structure (24),- an Ag-containing second functional layer (25),- an upper dielectric structure (26), and the total optical path (TDOT) of the upper dielectric structure (26) is at most 82 nm, including this value, the total optical path (BTOD) of the lower dielectric structure (21 ) is at least 65 nm, including this value, and the sum of the total optical path (TDOT) of the upper dielectric structure (26) and the total optical path (BTOD) of the lower dielectric structure (21 ) is 0.84-0.94 times the value of the total optical path (MDOT) of the intermediate dielectric structure (24).

2. A low-E coated glass according to claim 1 , characterized in that the second functional layer (22) is thicker than the first functional layer (25).

3. A low-E coated glass according to claim 1 , characterized in that the intermediate dielectric structure (24) comprises at least 3 layers of medium refractive index structured in a sandwich form, with the bottom and top having the same content.

4. A low-E coated glass according to claim 1 , characterized in thatthe upper dielectric structure (26) comprises a ZnAIOxlayer positioned over and in contact with the second functional layer (25).

5. A low-E coated glass according to claim 1 , characterized in that said lower dielectric structure (21 ) comprises at least one dielectric layer with a high refractive index and at least one layer with a medium refractive index.

6. A low-E coated glass according to claim 1 , characterized in that the lower dielectric structure (21) comprises preferably at least one dielectric layer with a high refractive index and at least two layers with a medium refractive index.

7. A low-E coated glass according to claim 1 , characterized in that said upper dielectric structure (26) comprises at least one layer with a medium refractive index.

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