LOW-E COATED GLASS WITH INCREASED TRANSMITTANCE

TECHNICAL FIELD

The present invention relates to a low emissivity (low-e) coated glass which transmits visible light in an efficient manner and which provides thermal control.

PRIOR ART

One of the factors which differentiate optic characteristics of glasses is the coating applications which are applied onto the glass surface. One of the coating applications is the magnetic field supported sputtering method in vacuum medium. This is a method frequently used particularly in the production of architecture and automotive coated glasses having low- e characteristic. By means of said method, the transmittance and reflection values of the coated glasses in the visible, near infrared and infrared region can be obtained at the targeted levels.

Besides transmittance and reflection values in the visible region, the total solar energy transmittance (g) value is also an important parameter in coated glasses to be used in architecture and automotive sectors. Since the total solar energy transmittance (g) value of coatings is high, they can be preferred for decreasing heating loads in cold climate regions. The total solar energy transmittance (g) values of coatings can be kept at the targeted levels by means of the number of the Ag layers included, the type of the seed layer used, and the parametric optimizations of layers.

In the patent with publication number EP0219273, a transparent article is disclosed comprising a base, at least four coated layers, and a top protective layer. The coated layers typically include a first dereflecting region, a transparent layer of silver or other metal, and a second dereflecting region comprising a layer of titanium dioxide, Ti02, and a layer of another dielectric material. A titanium dioxide layer may also be a component of the first dereflecting region. Each deflecting region that includes a titanium dioxide layer also comprises a layer of a transparent oxide or other dielectric material having an index of refraction intermediate between about 2.7, the approximate index of titanium dioxide, and the index of the nearby base or top layer, respectively. The intermediate index material is preferably zinc oxide because this material can be relatively quickly and inexpensively deposited by reactive sputtering. Moreover, a method is disclosed for depositing layers coated with sputtering and reactive sputtering for titanium and silver, zinc or other materials. The coating can be used as a component of a laminated window particularly for front glasses heated with electrical power for automobiles.

In the patent with publication number EP0219273, a transparent element is disclosed comprising a transparent base, a transparent first reflection layer, a transparent metallic layer, a titanium dioxide layer having thickness between 2 and 5 nanometers, a second dereflecting layer having a refraction index between 2.7 and the index of an upper layer, and an upper protective layer.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to a low-e coated glass, for bringing new advantages to the related technical field.

An object of the present invention is to provide a low-e coated glass having high visible region transmittance.

Another object of the present invention is to provide a thermally processable low-e coated glass.

Another object of the present invention is to provide a low-e coated glass which can be positioned both on the second surface (hereafter it will be described as the second face) and on the third surface (hereafter it will be described as the third face) of the thermal glass units when counted as from the atmosphere side depending on the total solar energy transmittance (g) requirement in thermal glass units.

In order to realize all of the abovementioned objects and the objects which are to be deducted from the detailed description below, the present invention is a single silver low-e coated glass having high visible region light transmittance and developed for use in thermal isolation unit applications. Accordingly, said invention is characterized by comprising the followings outwardly from the glass:

- a first dielectric layer comprising at least one of Si _x N _y , SiO _x N _y, ZnSnO _x , TiO _x , TiN _x , ZrN _x positioned in the vicinity of glass;

- a seed layer positioned on said first dielectric layer and comprising at least one of NiCr, NiCrO _x , TiO _x , ZnAIO _x , ZnO _x , - an infrared reflective layer,

- a barrier layer,

- a second dielectric layer,

- an upper dielectric layer comprising at least one of ZnSnO _x , ZnAIO _x , SiO _x N _y , SiO _x , Si _x N _y , TiO _x , ZnO _x and wherein said second dielectric layer comprises a high refraction index material selected from TiO _x , Nb _x O _y , Te _x O _y , ZrO _x which provides staying of the color values of the low-e coated glass in the negative region.

In a preferred embodiment of the present invention, the total optic path of the second dielectric layer and of the upper dielectric layer is equal to the total optic path of the first dielectric layer and of the seed layer.

In another preferred embodiment of the present invention, in accordance with the observation angle which is up to at least 45 degrees, the coating side and glass side reflection a* and reflection b* values color change defined in the CIE L a* b* space (hereafter it will be described as L and a* and b* value) is at most ±1.5 units.

In another preferred embodiment of the present invention, the second dielectric layer is TiO _x .

In another preferred embodiment of the present invention, the thickness of the second dielectric layer is between 5 nm and 20 nm.

In another preferred embodiment of the present invention, the followings are provided outwardly from the glass:

- said first dielectric layer comprises SiO _x N _y ,

- said seed layer comprises ZnAIO _x ,

- said reflective layer comprises Ag,

- said barrier layer comprises NiCrO _x ,

- said second dielectric layer comprises TiO _x ,

- said upper dielectric layer comprises SiO _x N _y.

In another preferred embodiment of the present invention, the followings are provided outwardly from the glass:

- the thickness of said first dielectric layer is between 10 nm and 35 nm,

- the thickness of said seed layer is between 15 nm and 35 nm,

- the thickness of an infrared reflective layer is between 7 nm and 15 nm,

- the thickness of said barrier layer is between 0.70 nm and 2.0 nm, - the thickness of said second dielectric layer is between 5 nm and 20 nm,

- the thickness of said upper dielectric layer is between 20 nm and 40 n .

In another preferred embodiment of the present invention, the reflection a* values before and after thermal process for the coating side and for the glass side are between -1 and -11.

In another preferred embodiment of the present invention, the reflection b* values before and after thermal process for the coating side and for the glass side are between -16 and -2.

In another preferred embodiment of the present invention, the reflection b* values before and after thermal process for the coating side and for the glass side are between -20 and -6.

In another preferred embodiment of the present invention, in case it is applied to the second face in thermal glass units, the total solar energy transmittance value of the thermal glass unit before and after thermal process is between 55% and 69%.

In another preferred embodiment of the present invention, in case it is applied to the third face in thermal glass units, the total solar energy transmittance value of the thermal glass unit before and after thermal process is between 62% and 76%.

BRIEF DESCRIPTION OF THE FIGURE

Figure 1 is a representative view of the low-e coated glass.

REFERENCE NUMBERS

10 Glass

20 Low-e coating

21 First dielectric layer

22 Seed layer

23 Infrared reflective layer

24 Barrier layer

25 Second dielectric layer

26 Upper dielectric layer DETAILED DESCRIPTION OF THE INVENTION

In this detailed description, the subject matter low-e coated (20) glass (10) is explained with references to examples without forming any restrictive effect only in order to make the subject more understandable.

The production of low-e coated (20) glasses (10) related to architecture and automotive is realized by means of“sputtering” method. The present invention essentially relates to low-e coated (20) glasses (10) with single silver whose thermal process resistance is high and used as thermal isolation glass (10) which transmits daylight and relates to the ingredient and application of said low-e coating (20).

In the present invention, a low-e coating (20) is developed comprising pluralities of metal, metal oxide and metal nitride/oxy-nitride layers positioned on the glass (10) surface by using sputtering method in order to obtain a low-e coated (20) glass (10) designed in a thermally processable manner and having high visible light transmittance in order to be applied onto the surface of a glass (10) such that the angular color change thereof is at acceptable level. Said layers are deposited on each other respectively under vacuum. As the thermal process, at least one of and/or a number of tempering, partial tempering, annealing and bending processes can be used. The subject matter low-e coated (20) glass (10) can be used as architecture and automotive glass (10).

In order to develop a low-e coating (20) sequencing which is preferred in terms of the production easiness and in terms of optic characteristics, the following data has been detected as a result of experimental studies.

In the subject matter low-e coated (20) glass (10), the refraction indices of all layers are determined by using calculation methods through optic constants obtained from single layer measurements taken. Said refraction indices are the refraction index data at 550 nm.

In the subject matter low-e coating (20), a first infrared reflective layer (23) is provided which transmits the visible region at the targeted level and which provides reflection of thermal radiation (by transmitting less) in the infrared spectrum. Ag layer is used as the infrared reflective layer (23) and its thermal emissivity is low. In order to reach the targeted performance value, the thickness of the infrared reflective layer (23) is substantially important. In the preferred application, the thickness of the infrared reflective layer (23) including Ag is between 7 nm and 15 nm. In a further preferred application, the thickness of the infrared reflective layer (23) including Ag is between 7 nm and 12 nm. Most preferably, the thickness of the infrared reflective layer (23) including Ag is between 7.5 nm and 10 n .

In the subject matter coating, a first dielectric layer (21) is used as the lowermost layer in a manner contacting glass (10). Said first dielectric layer (21) comprises at least one of Si _x N _y , SiO _x N _y , ZnSnO _x , TiO _x , TiN _x , ZrN _x layers. In the preferred application, as the first dielectric layer (21), a layer including SiO _x N _y is used. The first dielectric layer (21) including SiO _x N _y behaves as diffusion barrier and serves to prevent alkali ion migration which is facilitated at high temperature. Thus, the first dielectric layer (21) including SiO _x N _y supports resistance of the low-e coating (20) against thermal processes. The refraction index of the first dielectric layer (21) including SiO _x N _y is between 1.55 and 2.10. In the preferred structure, the refraction index of the first dielectric layer (21) including SiO _x N _y is between 1.70 and 2.00.

The thickness of the layer including SiO _x N _y and which is the first dielectric layer (21) is between 10 nm and 35 nm. In the preferred application, the thickness of the first dielectric layer (21) including SiO _x N _y is between 15 nm and 35 nm. In a further preferred application, the thickness of the layer including SiO _x N _y and which is the first dielectric layer (21) is between 20 nm and 30 nm.

At least one first seed layer (22) is positioned between the first dielectric layer (21) including SiO _x N _y and the first infrared reflective layer (23) including Ag. In an application of the present invention, the seed layer (22) directly contacts the first dielectric layer (21) including SiO _x N _y . The seed layer comprises at least one of NiCr, NiCrO _x , TiO _x , ZnAIO _x , ZnO _x . In the preferred application, the seed layer (22) comprises ZnAIO _x . The thickness of the seed layer (22) is between 10 nm and 35 nm. In the preferred application, the thickness of the seed layer (22) is between 15nm and 35nm. In a further preferred application, the thickness of the seed layer (22) is between 20 nm and 30 nm. Thanks to the usage of such thickness, the seed layer (22) including ZnAIO _x contributes to the sodium barrier function of the first dielectric layer

(21). As the seed layer (22) including ZnAIO _x is used within the mentioned thickness values, at the same time, the crystallization of the layer is increased and thus, a good sub-layer/base is provided for the infrared reflective layer (23) thereon. The refraction index of the seed layer

(22) including ZnAIO _x is between 1.90 and 2.10. In the preferred structure, the refraction index of the seed layer (22) including ZnAIO _x is between 1.95 and 2.05.

A barrier layer (24) is positioned on the infrared reflective layer (23). At least one of NiCr, NiCrO _x , TiO _x , ZnAIO _x layers is used as the barrier layer (24). In the preferred application, NiCrO _x is used as the barrier layer (24). The thickness of the barrier layer (24) including NiCrO _x is between 0.70 nm and 2.00 nm. In the preferred application, the thickness of the barrier layer (24) including NiCrO _x is between 0.75 nm and 1.70 nm. In the preferred application, the thickness of the barrier layer (24) including NiCrO _x is between 0.80 nm and 1.50 nm.

A second dielectric layer (25) is positioned on the barrier layer (24). Said second dielectric layer (25) comprises at least one of ZnSnO _x , ZnAIO _x , SiO _x N _y , SiO _x , Si _x N _y , TiO _x , Nb _x O _y , Ta _x O _y , Te _x O _y , ZnO _x, ZrO _x . Material with high refraction index including at least one of TiO _x , Nb _x O _y , Ta _x O _y , Te _x O _y , ZrO _x is used. In the preferred application, the second dielectric layer (25) comprises TiO _x . The thickness of the second dielectric layer (25) including TiO _x is between 5 nm and 20 nm. In the preferred application, the thickness of the second dielectric layer (25) including TiO _x is between 7.5 nm and 17.5 nm. Most preferably, the thickness of the second dielectric layer (25) including TiO _x is between 10 nm and 15 nm. The refraction index of the second dielectric layer (25) including TiO _x is between 2.35 and 2.65. In the preferred structure, the refraction index of the second dielectric layer (25) including TiO _x is between 2.40 and 2.60.

An upper dielectric layer (26) is positioned on the second dielectric layer (25). Said upper dielectric layer (26) comprises at least one of ZnSnO _x , ZnAIO _x , SiO _x N _y , SiO _x , Si _x N _y , TiO _x , ZnO _x . In the preferred application, the upper dielectric layer (26) comprises SiO _x N _y . The thickness of the upper dielectric layer (26) including SiO _x N _y is between 20 nm and 40 nm. In the preferred application, the thickness of the upper dielectric layer (26) including SiO _x N _y is between 22 nm and 38 nm. In the most preferred application, the thickness of the upper dielectric layer (26) including SiO _x N _y is between 24 nm and 36 nm. The refraction index of the upper dielectric layer (26) including SiO _x N _y is between 1.55 and 2.10. In the preferred structure, the refraction index of the upper dielectric layer (26) including SiO _x N _y is between 1.70 and 2.00.

Positioning of the second dielectric layer (25), including TiO _x , between glass (10) and the infrared reflective layer (23) including Ag, in other words, positioning of the second dielectric layer (25), including TiO _x , under infrared reflective layer (23) including Ag or positioning thereof between air and infrared reflective layer (23) including Ag, in other words, positioning thereof on the infrared reflective layer including Ag, creates difference in terms of optical performance.

Using the second dielectric layer (25) including TiO _x between air and infrared reflective layer (23) including Ag provides the coating side and glass side reflection values to be at the same level and provides the color values to be the same. Moreover, by means of this, the coating side and glass side reflection a* value stays in the negative region. Thus, formation of red color tones in the coating side and glass side reflection color values is prevented. By using the second dielectric layer (25), including TiO _x , on the infrared reflective layer (23) including Ag, the coating side and glass side reflection b* value stays in the negative region. Thus, formation of yellow color tones in the coating side and glass side reflection color values is prevented. As a result, the low-e coating (20) has the targeted color values.

Besides, the refraction indices and the physical thicknesses of the mentioned arrangement and the related dielectric layers are adjusted in a careful manner at the abovementioned ranges, and firstly, the targeted performance values are not changed and the coating side and the glass side reflection color tones are fixed at different observation angles up to at least 45°. By means of this, the low-e coating (20) can have an aesthetically and decoratively envisaged character.

In the subject matter arrangement, the second dielectric layer (25) including TiO _x is used between air and the infrared reflective layer (23) including Ag, and thereby, lower reflection values can be obtained without compromising the total solar energy transmittance (g) values and without visible region transmittance values of low-e coated (20) glass (10).

The low-e coating (20), obtained by means of the subject matter arrangement, can be preferred to be applied to the second face or to the third face for different total solar energy transmittance (g) values in the thermal glass units. When such a preference is made, said low-e coating (20) exhibits the same reflection character both outside the building and inside of the building in an independent manner from the position where it is positioned in the double-glass unit until the observation angles of 45° where thermal process is not applied and provides high transmittance for both surfaces and different total solar energy gain (g). This advantageous condition can be preferred for different thermal load calculations on different walls on the same building.

The low-e coating (20), obtained by means of the subject matter arrangement, can be preferred to be applied to the second face or to the third face for different total solar energy transmittance (g) values in thermal glass units. When such a preference is made, said low-e coating (20) exhibits the same reflection character both outside the building and inside of the building in an independent manner from the position where it is positioned in the double glass unit until the observation angles of 45° where thermal process is applied and provides high transmittance for both surfaces and different total solar energy gain (g). This advantageous condition can be preferred for different thermal load calculations on different walls on the same building.

In case the low-e coated (20) glass (10) is applied to the second face or to the third face in thermal glass units, before the thermal process and after the thermal process, Tvis values for both applications are between 70% and 83%. In the preferred application, in case the low-e coated (20) glass (10) is applied to the second face or to the third face in thermal glass units, Tvis values for both applications are between 71% and 82%. In the further preferred application, in case the low-e coated (20) glass (10) is applied onto the second face or to the third face in the thermal glass units, Tvis values for both applications are between 74% and 81%.

In case the low-e coated (20) glass (10) is applied onto the second face in thermal glass units, before and after the thermal process, the total solar power transmittance (g) values of the thermal glass unit are between 55% and 69%. In the preferred application, in case the low-e coated (20) glass (10) is applied to the second face in thermal glass units, before the thermal process and after the thermal process, the total solar energy transmittance (g) values of the thermal glass unit are between 57% and 67%. More preferably, in case the low- e coated (20) glass (10) is applied to the second face in thermal glass units, before the thermal process and after the thermal process, the total solar energy transmittance (g) values of the thermal glass unit are between 59% and 65%.

In case the low-e coated (20) glass (10) is applied to the third face in thermal glass units, before the thermal process and after the thermal process, the total solar energy transmittance (g) values of the thermal glass unit are between 62% and 76%. In the preferred application, in case the low-e coated (20) glass (10) is applied to the third face in thermal glass units, before the thermal process and after the thermal process, the total solar energy transmittance (g) values of the thermal glass unit are between 64% and 75%. More preferably, in case the low-e coated (20) glass (10) is applied to the third face in thermal glass units, before the thermal process and after the thermal process, the total solar energy transmittance (g) values of the thermal glass unit are between 67% and 73%.

The coating side and the glass side reflection a* values of the low-e coated (20) glass (10) before and after the thermal process are between -1 and -11. In the preferred application, the coating side and the glass side reflection a* values of the low-e coated (20) glass (10) before and after the thermal process are between -1 and -9. In a further preferred application, the coating side and the glass side reflection a* values of the low-e coated (20) glass (10) before and after the thermal process are between -1 and -7.

The reflection luminosity L values of the low-e coated (20) glass (10) before and after the thermal process are low for the coating side and glass side surfaces and as a result of this, the distinguishability of the difference level in reflection b* values by means of observation decreases.

The coating side and glass side reflection b* values of the low-e coated (20) glass (10) before the thermal process are between -16 and -2. In the preferred application, the coating side and glass side reflection b* values of the low-e coated (20) glass (10) before the thermal process are between -14 and -4. In a further preferred application, the coating side and glass side reflection b* values of the low-e coated (20) glass (10) before the thermal process are between -12 and -6.

The coating side and glass side reflection b* values of the low-e coated (20) glass (10) after the thermal process are between -20 and -6. In the preferred application, the coating side and glass side reflection b* values of the low-e coated (20) glass (10) after the thermal process are between -18 and -8. In a further preferred application, the coating side and glass side reflection b* values of the low-e coated (20) glass (10) after the thermal process are between -16 and -10.

The low-e coating (20), obtained by means of the subject matter arrangement, can be used with or without thermal process on the second faces or on the third faces in thermal glass units. By means of these usage alternatives, thermal glass units with different total solar energy gain can be obtained such that the reflection color characteristic is substantially fixed. Besides all of these characteristics, various solution alternatives are formed particularly in architectural applications such that the visible region transmittance is fixed.

The protection scope of the present invention is set forth in the annexed claims and cannot be restricted to the illustrative disclosures given above, under the detailed description. It is because a person skilled in the relevant art can obviously produce similar embodiments under the light of the foregoing disclosures, without departing from the main principles of the present invention.