EA043067B1 - SPECIAL COATED GLASS FOR VIG ASSEMBLY - Google Patents

Description

Technical field

The present invention relates to a glass sheet (or panel) coated with a magnetron-sputtered coating, such as a low-e coating. The coated glass sheet of the present invention is particularly suitable as part of a vacuum insulated glass (VIG, or vacuum IG) unit. VIG is usually made from two sheets of glass, wherein the main surface of at least one of these sheets of glass, which is oriented in the direction of the interior space between the two sheets of glass, is provided with a coating, such as a coating deposited by magnetron sputtering. Such a VIG can be used, for example, in applications to building openings (windows and doors), in vehicles and refrigerator doors.

State of the art

Vacuum-insulated double-glazed windows are characterized by a high thermal insulating capacity, where the thermal transmittance, U, is less than 1.2 W/m ² K. This efficiency is a direct consequence of the low thermal conductivity in vacuum and thus depends on the quality of the vacuum and its stability.

The assembly of the VIG can be accomplished by various known methods with the same goal of having a stable vacuum cavity formed between two hermetically sealed glass panels that are held apart by separate spacers (or struts). The vacuum cavity is characterized by a pressure level not exceeding 0.1 mbar. Various types of seal material and various types of spacers are known in the art. Typical sealants for VIG are glass solders (also called solder glass) and metal or ceramic solders. One of the most modern sealants is based on solder glass, which has a lower melting point than glass. The use of solder glass, however, limits the choice of low emissivity layers to those layers that are not destroyed by the thermal cycle required for solder glass deposition, i.e. layers capable of withstanding temperatures, possibly up to 250° C. or even more. An alternative are metal seals, such as soft tin or copper alloy solders, which also have the advantage that they partially deform and thus partially absorb the relative expansion between the first and second glass panels when they are subjected to a temperature gradient along VIG thickness. Additionally, in order to keep both glass panels stably at a distance from one another, an array of separate spacers (or racks) must be placed between these two glass panels. The individual spacers may have different shapes, such as cylindrical, spherical, thread-like, hourglass-shaped, C-shaped, cruciform, prismatic, and so on. It is preferable to use small racks, i.e. racks having a common surface of contact with the glass panel, limited by their outer circumference, less than or equal to 5 mm ² , preferably less than or equal to 3 mm ² , more preferably less than or equal to 1 mm ² . These values can provide good mechanical strength while remaining aesthetically uncoupled.

Individual spacers are typically made of a material that is strong enough to withstand the pressure applied by the surfaces of the glass panels and is capable of withstanding high temperature processes such as firing and annealing, and that releases little gas after VIG sealing. Such material is preferably a hard metal material, quartz glass or ceramic material. In particular, it may be a metal material such as iron, tungsten, nickel, chromium, titanium, molybdenum, carbon steel, chromium steel, nickel steel, stainless steel, nickel-chromium steel, manganese steel, chromium-manganese steel, chromium-molybdenum steel, silicon steel, nichrome, duralumin, and the like, or it may be a ceramic material such as corundum, alumina, mullite, magnesia, yttrium oxide, aluminum nitride, silicon nitride, and the like.

To maintain a vacuum over time, a getter is placed in the VIG. Usually this getter is based on a metal alloy, such as, for example, based on zirconium, iron, cobalt and/or aluminum. The getter is placed as a thin layer or block in a hermetically sealed space between two glass panels. Once activated, the getter will absorb gases released during the life of the VIG in order to maintain a vacuum.

There are various ways to build a VIG. The assembly method described in EP 2 851 351 A1, the contents of which are incorporated herein by reference in their entirety, includes three main steps, which may overlap. First of all, the first glass panel is placed horizontally, the glass solder is deposited, the racks are placed and the second glass panel is laid on top, the first heating period to 450°C provides thermal sealing of both glass panels at their outer edges, which leaves space between them. The second stage is pumping out internal gases to a residual pressure of no more than 0.1 mbar. With regard to the formation of vacuum in the interior of an insulating glass unit, usually a hollow glass tube is provided on the main surface of one of the glass sheets, connecting the interior to the outside. Thus, a vacuum is created in the internal space by pumping out gases,

- 1 043067 located in the inner space, by means of a pump connected to the outer end of the glass tube. Moreover, the production method according to EP 2851351 A1 describes a method for manufacturing vacuum insulated glazing, which includes: (a) hermetically bonding, using a hermetic bonding element, the perimeters of paired glass panels located facing each other at a predetermined distance to form a space, hermetically closed between glass panels; (b) removing air from this space through an outlet in order to make this space in a state of reduced pressure; and (c) dividing the space, by means of a region-forming member, into an outlet region containing the outlet and a reduced pressure region other than the outlet region. The region-forming element comprises an air channel connecting the outlet region with the region of reduced pressure in the formation of the space. After the space is made in a reduced pressure state, the space is divided into an outlet area and a reduced pressure area by closing off the air passage; thus, the ends of the region-forming element are connected to the sealing element, surrounding the outlet opening together with the sealing element. The sealing element and the region-forming element are made using the same low melting glass solder. EP 2 851 351 A further makes reference to paragraphs [0034]-[0054] which describe a first method for producing the assembled VIG shown in FIG. 1-4 and 6, which, as shown in FIG. 5 includes a first melting method at 450°C to seal the perimeters of the glass panels; a vacuum method in which the temperature of the furnace is reduced below the melting temperature of the glass solder equal to 434°C to create a vacuum; and the second melting method at 465° C. completes the removal of air and the sealing of the vacuum opening. In paragraphs [0056]-[0079] and in FIG. 7 describes a variant of the above-described production method in which the assembly temperature of the panels after the first melting method is lowered to room temperature. EP 1 506 945 A1, for example, describes the use of such a glass tube which is welded in position in a through hole made in the main surface of one of the glass sheets. During this second step, the temperature is lowered to some extent and the glass panels are brought closer together until they reach the pillars that form the free space. The final space between two glass panels is characterized by a size of no more than 2 mm. The third step includes a second heating period to 465°C to ensure the posts adhere to the glass panels and complete the hermetic seal. This technical solution impairs the aesthetic appearance of the glass panel, since not a single visible protrusion is formed on the surface of one of the glass sheets.

Another possibility to further increase the insulating power of the VIG is to use a solar control or low-e coating on one or more surfaces of the glass panels used in the VIG assembly. Preferably, a sunscreen or low emissivity coating is deposited on the surface of the glass panel, which will be oriented in the direction of the VIG vacuum space. Due to the presence of high temperature sealants and possible additional treatments, it is necessary that the coating be resistant to high temperature treatments. For example, US5657607A describes a low e coating for VIG but is silent on any compatibility of this low e coating with assembly conditions. In a second example, US1001219B2, layers of ITO, tin oxide, or tin metal are mentioned as low emissivity coatings to be included in a VIG package, but the purpose of this patent is to assemble this VIG package at a lower temperature. US Pat. No. 1,001,219 B2 gives no indication of vacuum stability in the case of a reheat method after a VIG hermetic seal.

The inventors have observed that when performing a VIG assembly method similar to the methods described in EP 2 851 351 A1 for assembling two glass panels, one of which is coated with a low emissivity coating, some new, unexpected problems arise. Although the target vacuum was reached after the final sealing step was completed, the performance of the VIG package varied. The inventors have surprisingly found that this problem is due to the presence of a noble gas introduced into the low-e coating, which is released after VIG compaction. This noble gas has been found to be derived from a low e coating deposition process that provides a low e coating containing a noble gas, typically argon. As a consequence, in particular for the VIG, during the production process it turns out that after vacuuming and sealing the VIG assembly, the high temperature still present is responsible for the additional release of gas, which affects the final residual pressure in the VIG package and , as a consequence, on the thermal characteristics of the VIG package. It has been found that, under these circumstances, noble gas release may occur during the manufacturing process and/or during the life of the glazing. In addition, it has been found that in the case of a noble gas, a getter placed inside the cavity of a vacuum insulated glazing is ineffective in capturing it and maintaining a vacuum level.

This study demonstrates the need to determine the noble gas concentration tolerable in a low-e coating deposited on a glass panel, particularly for use in a VIG assembly. At the same time, the presence of argon is essential for the sputter deposition process of some materials and is often key to an efficient, cost-effective process.

It also shows that there is a need to define specific coating conditions to enable sputter deposition of a low e coating that satisfies the condition associated with the maximum noble gas concentration in the low e coating and in particular in the low e coating layers in addition to the functional layer, i.e. . typically a metallic radiation-reflecting functional layer, and a protective barrier deposited on said functional layer.

The essence of the invention

The present invention relates to a glass substrate (also referred to as a glass sheet or glass panel) coated with a sputtered low emissivity coating, which has the highest noble gas concentration in the low emissivity coating. The coated glass sheet is such that the release of a noble gas under certain vacuum conditions does not exceed a certain amount which directly correlates with the total molar amount of said noble gas released.

Therefore, in its first embodiment, the present invention relates to a coated glass panel in which the threshold amount of noble gas in the low-e coating is not exceeded, and thus it is characterized by a content of liberated noble gas in the coated glass panel under pressure of less than 10 ^-6 mbar. and after heating from room temperature to 460°C in 100 min, holding at 460°C for 20 min and cooling from 460 to 23°C in 100 min, less than 1.5x10' ⁶ mbar^cm ³ per mm ² of the area containing the coating the surface of a coated glass panel measured by the noble gas liberated measurement (ONGM) described below.

Therefore, in its first embodiment, the present invention relates to a coated glass panel which comprises a glass substrate provided with a low emissivity coating comprising an alternating arrangement of n infrared reflective functional layers and n+1 dielectric coatings, where n>1, such that each reflective IR functional layer is surrounded by dielectric coatings, wherein the dielectric coating comprises one or more dielectric layers, and so that each infrared reflective functional layer is protected by a barrier layer immediately above and in contact with it, with at least one layer in addition to each the infrared reflective functional layer and the barrier layer contain a noble gas, preferably argon.

The low emissivity coating may further comprise a protective surface coating, optionally containing one or more dielectric layers. The low emissivity coating may also further comprise a seed layer, optionally comprising a dielectric layer and located under and in contact with at least one infrared reflective functional layer.

In the low-e coating of the coated glass panel according to the present invention, at least one layer in addition to the infrared reflective functional layer and the barrier layer is a dielectric layer of a dielectric coating, a seed layer, and/or a protective surface coating. The total geometric thickness of the dielectric layers deposited in an atmosphere containing a noble gas is at least 30 nm and not more than 120 nm.

The coated glass panel according to the present invention is characterized by a content of liberated noble gas, based on the area of the coated surface of the coated glass panel, under a pressure of less than 10 ^-6 mbar and after heating from room temperature to 460° C. for 20 min and cooling from 460 to 23°C in 100 min less than 1.5x10' ⁶ mbar^cm ³ per mm ² coated glass panel.

To achieve this goal, the present invention defines sputtering conditions for depositing a low-e coating on a glass panel that make it possible to satisfy the above-described noble gas threshold. Thus, in one embodiment, the present invention relates to a method for manufacturing a coated glass panel, which includes delivering a glass substrate to a magnetron sputtering facility and depositing layers on the glass substrate using reduced pressure cathode sputtering, in which:

i) the IR-only functional layer(s) and the barrier layer(s) are deposited in an atmosphere containing 95 to 100% noble gas, preferably argon;

- 3 043067 ii) metal oxide dielectric layers from metal targets are deposited in an atmosphere containing from 95 to 100% oxygen;

iii) the other dielectric layers are deposited in such an atmosphere that the volume fraction of the noble gas in the gaseous medium does not exceed 90%.

In another embodiment, the present invention also relates to means for removing excess noble gas present in the low-e coating prior to assembling the coated glass sheet into a VIG package such that the coated glass satisfies the noble gas threshold condition described above. The means according to this embodiment include a method for pre-annealing the low e-coated glass. Thus, in a glass with a low-e coating, the noble gas threshold condition is met, whatever the deposition conditions of the coating. During this process, any excess noble gas can be removed by heating the coated glass, preferably under vacuum. In this embodiment, the coated glass panel is heat treated at a temperature of over 300°C, preferably 400°C, and more preferably 480°C.

The present invention further relates to coated glass panels produced by any of the methods described above. The present invention also relates to the use of a coated glass panel for the manufacture of vacuum insulated glazing, and ultimately the present invention relates to vacuum insulated glazing comprising this coated glass panel.

Detailed description

The present invention addresses the technical problem of providing and making a coated glass panel, in particular for vacuum insulated glazing applications. Noble gas is considered to be a cost-effective and efficient precipitating gas for use in the magnetron sputtering process, so it is commonly used in the production of coated glass panels. However, it has been surprisingly found that coated glass panels in which one or more layers of a low-e coating have been deposited with a noble gas do not provide the required thermal performance when incorporated into assemblies, particularly vacuum insulated glazing. Thus, the present invention is based on limiting the amount of noble gas released by such coated glass panels.

According to the present invention, the low-e coating contains at least one layer of coating deposited using a magnetron. In one embodiment of the present invention, a low-e coating of a coated glass panel comprises: an alternating arrangement of n infrared reflective functional layers and n+1 dielectric coatings, where n>1, such that each infrared reflective functional layer is surrounded by dielectric coatings, wherein the dielectric the coatings comprise one or more layers of dielectric material, and such that each infrared reflective functional layer is protected by a barrier layer immediately above and in contact with it; An n-positive integer greater than or equal to 1 (n>1). Preferably, an n-positive integer less than or equal to 3 (n<3), more preferably n is 1 or 2. It has been found that such a limited number of alternating arrangements provides the right balance between the thermal performance of the glazing assembly in which the glass coated glass panel, and production costs of such coated glass panel.

As described herein, the dielectric coating is made up of one or more layers made from dielectric materials, hereinafter referred to as dielectric layers. The dielectric coating may also be referred to as a dielectric film. The coated glass panel may further comprise a protective surface coating, which optionally comprises one or more dielectric layers; and/or a seed layer, optionally comprising a dielectric layer, under and in contact with the at least one infrared reflective functional layer. Therefore, at least one layer, in addition to the infrared reflective functional layer and the barrier layer, may be a dielectric layer derived from a dielectric coating, a seed layer and/or a protective surface coating.

Thus, with n=1, the low-e coating deposited on a glass substrate according to the present invention is an alternating arrangement that contains at least the following order, starting from the surface of the glass substrate:

a dielectric coating made from one or more dielectric layers;

an infrared reflective functional layer;

barrier layer;

a dielectric coating made from one or more dielectric layers.

Thus, at n=2, the low-e coating deposited on a glass substrate according to the present invention is an alternating arrangement that contains at least the following order, starting from the surface of the glass substrate:

a dielectric coating made from one or more dielectric layers;

an infrared reflective functional layer;

barrier layer;

a dielectric coating made from one or more dielectric layers;

an infrared reflective functional layer;

barrier layer;

a dielectric coating made from one or more dielectric layers.

In particular, according to one embodiment of the present invention, the low-e coating deposited on a glass substrate according to the present invention is an alternating arrangement comprising at least the following order, starting from the surface of the glass substrate:

dielectric coating made of one or more dielectric layers, which has a geometric thickness in the range of 20 to 40 nm, an optional seed layer, preferably containing ZnO, which has a geometric thickness in the range of 2 to 10 nm, reflecting infrared radiation functional layer, preferably containing Ag, which has a geometric thickness in the range of 8 to 18 nm, a barrier layer, preferably containing ZnO, which has a geometric thickness in the range of 1 to 12 nm, preferably 2 to 8 nm, dielectric a coating made of one or more dielectric layers, which has a geometric thickness in the range of 40 to 100 nm, preferably 60 to 100 nm, an optional seed layer, preferably containing ZnO, which has a geometric thickness in the range of 2 to 10 nm infrared reflective functional layer preferably containing Ag having a geometric thickness ranging from 8 to 18 nm, a barrier layer preferably containing ZnO having a geometric thickness ranging from 1 to 12 nm, preferably from 2 to 8 nm, a dielectric coating made of one or more dielectric layers, which has a geometric thickness in the range of 10 to 45 nm, and an optional protective surface coating containing one or more dielectric layers and has a geometric thickness in the range from 1 to 10 nm.

At least one layer, in addition to each infrared-reflecting functional layer and the barrier layer, contains a noble gas, preferably argon. This layer, for example, may be a single layer of a dielectric coating, a seed layer and/or a protective surface coating. Moreover, in a cost-effective commercial magnetron sputtering process in a noble gas atmosphere, as many layers as possible should be deposited.

It has been found that since such layers are deposited in a noble gas atmosphere, some of the noble gas is indeed captured by the corresponding low emissivity coating. When such a coated glass panel is used in a glazing assembly whose production method requires a high temperature, the noble gas can diffuse through the coating and be released.

In the coated glass panel according to the present invention, the content of the liberated noble gas based on the area of the coated surface of the coated glass panel under pressure is less than 10'6 mbar and after heating from room temperature to 460°C in 100 minutes, holding at 460°C for for 20 min and cooling from 460 to 23°C in 100 min is less than 1.5x10'6 mbar^cm ³ per mm ² coated glass panel.

In one embodiment of the present invention, the content of the liberated noble gas, based on the area of the coated surface of the coated glass panel under pressure, is less than 10'6 mbar and after heating from room temperature to 460°C in 100 minutes, holding at 460°C for 20 min and cooling from 460 to 23°C in 100 min is less than 1.0x10'6 mbar^cm ³ per mm ² coated glass panel, preferably less than 0.5x10'6 mbar^cm ³ per mm ² coated glass panel.

In another embodiment, the total geometric thickness of the noble gas deposited dielectric layers of the coated glass panel of the present invention is at least 35 nm, alternatively at least 40 nm, alternatively at least 45 nm, and alternatively at least 60 nm. In another embodiment, the total geometric thickness of the dielectric layer deposited in an atmosphere containing argon is at most 100 nm and more preferably at most 90 nm.

Therefore, the total geometric thickness (TGT) of the dielectric layer(s) deposited in an atmosphere containing a noble gas, in particular argon, is in the range of 30 to 120 nm (30 nm > TGT > 120 nm). In a preferred embodiment of the present invention, the total geometric thickness (TGT) of the dielectric layer(s) deposited in a noble gas atmosphere is between 35 and 120 nm (35 nm > TGT > 120 nm), preferably between 40 up to 100 nm (40 nm > TGT > 100 nm), more preferably 45 to 100 nm (45 nm > TGT > 100 nm) and most preferably 60 to 90 nm (60 nm > TGT > 90 nm). It has been found that such a limited thickness of the dielectric layers deposited in an atmosphere containing a noble gas, in particular argon, provides the right balance between the performance of a glazing assembly incorporating a coated glass panel and the production costs of such a coated glass panel. .

In another embodiment of the present invention, the infrared reflective functional layer(s) of the low-e coating comprises or consists of silver. In another preferred embodiment of the present invention, the geometrical thickness of the infrared reflective functional layer(s) of the low-e coating, preferably containing Ag, is 8 to 18 nm, preferably 8 to 16 nm, and most preferably 10 to 14 nm.

In another preferred embodiment of the present invention, the last dielectric layer of the last dielectric coating of the low-e coating contains a noble gas, preferably argon, and has a geometric thickness ranging from 1 to 30 nm, preferably from 10 to 30 nm, more preferably from 20 to 30 nm .

In another embodiment of the present invention, the coated glass panel comprises, from the glass substrate to the outside: a) a mixed tin-zinc oxide layer; b) a layer based on zinc oxide; c) a layer of silver; d) barrier layer; f) dielectric film (dielectric coating). Thus, in this embodiment, the positive integer n is 1 (n=1). In another embodiment of the present invention, the coated glass panel comprises, from the glass substrate to the outside: a) a mixed tin-zinc oxide layer; b) a layer based on zinc oxide; c) a layer of silver; d) barrier layer; f) dielectric film (dielectric coating); f) zinc oxide layer; g) second layer of silver; h) barrier layer; i) dielectric film (dielectric coating). Thus, in this embodiment, the positive integer n is 2 (n=2).

In another embodiment of the present invention, the low-e coating barrier layer comprises a metal or a metal alloy and/or an oxide and/or a nitride of that metal or metal alloy. The metal or metal alloy may be selected from the list consisting of titanium, zinc, nickel, chromium, niobium, and any alloy containing one of these metals. In particular, the barrier is a zinc oxide barrier, in particular an aluminium-doped zinc oxide layer or a substantially pure zinc oxide layer.

In another embodiment of the present invention, the dielectric film or dielectric coating comprises one or more dielectric layers containing any of the oxides or nitrides of titanium, silicon, zinc, tin, zirconium, or a mixture thereof.

In another embodiment of the present invention, a protective surface coating may be provided over the low-e packet. Moreover, the protective surface coating is the last layer of the low-e coating furthest from the surface of the substrate. The protective surface coating provides the function(s) of additional mechanical and/or chemical protection of the low-e coating. The protective surface coating may comprise one or more layers selected from the group which consists of any of the typical dielectric layers, metallic layers, and ultimately may be combined with a carbon layer or a temporary protective layer that is deactivated during heating.

When present in the form of a typical dielectric layer or metal layer, the thickness of such a protective surface coating should be taken into account when calculating the total geometric thickness of the dielectric layers deposited in a noble gas atmosphere.

In another aspect of the present invention, a coated glass panel according to the present invention is produced according to a method comprising the following steps: delivering a glass substrate to a magnetron sputtering facility, depositing layers on the glass substrate by magnetron sputtering under reduced pressure, and the deposition conditions are characterized in that:

i) only the infrared reflective metal layer(s) and the barrier layer(s) are deposited in an atmosphere containing 95 to 100% noble gas, preferably argon;

ii) metal oxide dielectric layer(s) is deposited from metal targets in an atmosphere containing 95 to 100% oxygen;

- 6 043067 iii) other dielectric layers are deposited in such an atmosphere that the volume fraction of the noble gas in the gaseous medium does not exceed 90%. In other words, in an atmosphere containing 95 to 100% noble gas, preferably argon, only the infrared reflective functional layer(s) and the barrier layer(s) are deposited.

Dielectric layers:

a) deposited from metal targets in an atmosphere containing 95 to 100% oxygen if they are metal oxide layers; And

b) deposited in such an atmosphere that the volume fraction of the noble gas in the atmosphere does not exceed 90%, unless they are metal oxide layers.

Therefore, in such a production method, the infrared reflective metal layer(s) and the barrier layer(s) are deposited in an atmosphere containing a noble gas, preferably argon, volume fraction of 95-100%. This means that the volume of the noble gas, preferably argon, relative to the volume of the total atmosphere gas is in the range of 95 to 100% (95%<[volume of noble gas/volume of total gas environment]<100%). Preferably, the noble gas volume fraction is in the range of 97 to 100%, and preferably 100% noble gas. A very limited amount of oxygen and/or nitrogen is acceptable.

In the dielectric coating, the metal oxide dielectric layer(s) that is(are) deposited from the metal target are, in particular, deposited in an atmosphere containing a volume fraction of oxygen from 95 to 100% and preferably 100% oxygen. This means that the volume of oxygen relative to the volume of the total atmosphere is in the range of 95 to 100% (95%<[volume of oxygen/volume of total atmosphere]<100%).

The other layer(s), which can be enclosed within the dielectric coating(s), and which is not a metal oxide dielectric layer(s) obtained from a metal target, is deposited in an atmosphere which contains a noble gas volume fraction in the entire gaseous medium not exceeding 90%. This means that the volume of the noble gas, preferably argon, is less than or equal to 90% relative to the volume of the total gaseous medium ([volume of noble gas/volume of the total gaseous medium]<90%).

It has been unexpectedly found that under such deposition conditions, the low emissivity coating formed on the glass substrate to form the coated glass panel of the present invention is such that the content of the liberated noble gas, based on the area of the coated surface of the pressure coated glass panel, is 10 ^-6 mbar and after heating from room temperature to 460°C in 100 min, holding at 460°C for 20 min, cooling from 460 to 23°C in 100 min is less than 1.5x10' ⁶ mbar ^ cm ³ per mm ² coated glass panels. Thus, the present invention covers a coated glass panel which has been produced by said method. In particular, the present invention further relates to a coated glass panel comprising a glass substrate provided with a low emissivity coating, said low emissivity coating comprising:

a) alternating arrangement of n infrared reflective functional layers and n+1 dielectric coatings, where n>1,

a. such that each infrared reflective functional layer is surrounded by dielectric coatings, wherein the dielectric coating comprises one or more dielectric layers, and

b. so that each infrared-reflecting functional layer is protected by a barrier layer immediately above and in contact with it, wherein at least one layer, in addition to each infrared-reflecting functional layer and the barrier layer, contains a noble gas, preferably argon,

b) optionally, a protective surface coating, optionally containing one or more dielectric layers;

c) optionally, a seed layer, optionally comprising a dielectric layer under and in contact with the at least one infrared reflective functional layer;

wherein at least one layer, in addition to each infrared-reflecting functional layer and the barrier layer, is a dielectric layer of a dielectric coating, a seed layer and/or a protective surface coating, and the total geometric thickness of the dielectric layers deposited in an atmosphere containing a noble gas , is at least 30 nm and not more than 120 nm; and at the same time, the content of the released noble gas based on the area of the coated surface of the coated glass panel under pressure is less than 10 ^-6 mbar and after heating from room temperature to 460°C for 100 minutes, holding at 460°C for 20 minutes and cooling from 460 to 23°C in 100 minutes is less than 1.5 x 10' ⁶ mbar^cm ³ per mm ² coated glass panel;

and wherein such a coated glass panel is manufactured according to a method comprising the steps of delivering a glass substrate to a magnetron sputtering facility and depositing layers on

- 7 043067 glass substrate using magnetron sputtering under reduced pressure, while the deposition conditions are as follows:

1) only the infrared reflective metal layer and the barrier layer are deposited in an atmosphere containing 95% to 100% noble gas, preferably argon;

2) metal oxide dielectric layers are deposited from metal targets in an atmosphere containing 95 to 100% oxygen;

3) other dielectric layers are deposited in such an atmosphere that the volume fraction of the noble gas in the gaseous medium does not exceed 90%.

In a preferred embodiment, the present invention encompasses a coated glass panel which has been produced by said method and in which the total geometric thickness of the layers deposited in a noble gas atmosphere is in the range of 35 to 120 nm (35 nm > TGT > 120 nm ), more preferably 40 to 100 nm (40 nm > TGT > 100 nm), most preferably 45 to 100 nm (45 nm > TGT > 100 nm) and even more preferably 60 to 90 nm (60 nm > TGT > 90 nm).

In a preferred embodiment, the present invention further relates to the above-described coated glass panel, in which the last layer of the low-e coating, preferably the last dielectric layer of the last dielectric coating, is deposited in an atmosphere containing 1 to 50%, preferably 1 to 45%, more preferably 5 to 40% noble gas, preferably argon. This means that the volume of the noble gas relative to the volume of the total gaseous medium is in the range of 1 to 50% (1%<[noble gas volume/total gaseous volume]<50%), preferably 1 to 45% (1%<[ noble gas volume/total gas volume]<45%), more preferably 5 to 40% (5%<[noble gas volume/total gas volume]<40%).

In another aspect of the present invention, a coated glass panel according to the present invention is manufactured according to a method comprising, in sequence, delivering the glass substrate to a magnetron sputtering facility, depositing layers on the glass substrate using magnetron sputtering under reduced pressure, heat treatment at a temperature of more than 300°C. , preferably 400°C and more preferably 480°C. Such a method can be called an annealing method.

Alternatively, the heat treatment can be carried out at a pressure of less than 1 bar, preferably less than or equal to 10 mbar, more preferably less than or equal to 1 mbar, and most preferably less than or equal to 0.1 mbar. Heat treatment can be carried out by maintaining the specified temperature for a time of at least 0.5 hours, preferably at least 2 hours and more preferably at least 6 hours, depending on the operating temperature and pressure.

Thus, the present invention covers a coated glass panel which has been produced by said method. In particular, the present invention also relates to a coated glass panel comprising a glass substrate provided with a low emissivity coating, said low emissivity coating comprising:

a) alternating arrangement of n infrared reflective functional layers and n+1 dielectric coatings, where n>1, so that each infrared reflective functional layer is surrounded by dielectric coatings, while the dielectric coating contains one or more dielectric layers, and so that each infrared reflective functional layer is protected by a barrier layer immediately above and in contact with it;

wherein at least one layer, in addition to each infrared-reflecting functional layer and the barrier layer, contains a noble gas, preferably argon,

b) optionally, a protective surface coating, optionally containing one or more dielectric layers,

c) optionally, a seed layer, optionally comprising a dielectric layer under and in contact with at least one infrared reflective functional layer;

wherein at least one layer, in addition to each infrared-reflecting functional layer and the barrier layer, is a dielectric layer of a dielectric coating, a seed layer and/or a protective surface coating, and the total geometric thickness of the dielectric layers deposited in an atmosphere containing a noble gas , is at least 30 nm and not more than 120 nm; and at the same time, the content of the released noble gas, based on the area of the coated surface of the coated glass panel under pressure, is less than 10'6 mbar and after heating from room temperature to 460°C in 100 minutes, holding at 460°C for 20 minutes and cooling from 460 to 23°C in 100 minutes is less than 1.5x10'6 mbar^cm ³ per mm ² coated glass panel.

- 8 043067

Wherein, such a coated glass panel is produced by a method which includes, in sequence, the following steps:

delivery of the glass substrate to the magnetron sputtering facility, deposition of layers on the glass substrate by magnetron sputtering under reduced pressure, and heat treatment at a temperature of more than 300°C (Temp>300°C), preferably more than 400°C (Temp>400°C ) and more preferably more than 480°C (Temp>480°C).

In a preferred embodiment, the present invention encompasses a coated glass panel which has been produced by said method and in which the total geometric thickness of the layers deposited in a noble gas atmosphere is in the range of 35 to 120 nm (35 nm > TGT > 120 nm ), more preferably 40 to 100 nm (40 hm>TGT>100 nm), most preferably 45 to 100 nm (45 hm>TGT>100 nm) and even more preferably 60 to 90 nm (60 hm>TGT> 90 nm).

In such methods, the heat treatment step can be carried out at a pressure of less than 1 bar, preferably less than 10 mbar, more preferably less than 1 mbar, and most preferably less than 0.1 mbar. In such methods, the heat treatment step can be performed by maintaining said temperature for a time of at least 0.5 hours, preferably at least 2 hours, and more preferably at least 6 hours, depending on the operating temperature and pressure.

In one embodiment of the present invention, to produce the coated glass panel of the present invention, the deposition conditions of a particular sputtering process may be combined with the heating step of the annealing process.

In another aspect of the present invention, a coated glass panel is used as part of a vacuum insulated glazing, with the low-e coating facing the vacuum space of the VIG package. Therefore, the present invention encompasses vacuum insulated glazing which comprises a coated glass panel provided with a low-e coating, said low-e coating comprising: a) an alternating arrangement of n infrared reflective functional layers and n+1 dielectric coatings, where n>1, so that each infrared reflective functional layer is surrounded by dielectric coatings, wherein the dielectric coating comprises one or more dielectric layers, and such that each infrared reflective functional layer is protected by a barrier layer directly above and in contact with it, wherein at least one layer, in addition to each infrared-reflecting functional layer and barrier layer, contains a noble gas, preferably argon,

b) optionally, a protective surface coating, optionally containing one or more dielectric layers,

c) optionally, a seed layer, optionally comprising a dielectric layer under and in contact with at least one infrared reflective functional layer, wherein at least one layer in addition to each infrared reflective functional layer and barrier layer is a dielectric layer of dielectric coating, seed layer and/or protective surface coating, and at the same time the total geometric thickness of the dielectric layers deposited in an atmosphere containing a noble gas is at least 30 nm and not more than 120 nm, and the content of the released noble gas in the calculation on the area of the coated surface of the coated glass panel under pressure less than 10'6 mbar and after heating from room temperature to 460°C in 100 minutes, holding at 460°C for 20 minutes and cooling from 460 to 23°C in 100 minutes is less than 1.5x10'6 mbar^cm ³ per mm ² of the coated glass panel.

In an aspect of the present invention, a vacuum insulated glass unit comprising at least one coated glass panel according to the present invention has a U value of not more than 1.00 W/m ² K, more preferably not more than 0.90 W/m ² K, and most preferably not more than 0.80 W/m ² K.

Moreover, the assembly of a VIG stack containing at least one coated glass panel according to the present invention will achieve a satisfactory vacuum despite the need for high temperature to finally seal the vacuum space. In addition, with the coated glass panel of the present invention, satisfactory vacuum stability is obtained regardless of what additional operations or influences may take place. A VIG comprising a coated glass panel of the present invention is designed to withstand harsh environmental conditions, such as conditions typically characterized by high operating temperatures, as well as exposure to shock and vibration, humidity, contaminants, radiation, and/or the like. For example, in glazed roofs, glazing systems are exposed to extreme temperatures (150°C) as well as shock and vibration load associated with wind loads.

- 9 043067

The present invention further relates to the use of a coated glass panel comprising a glass substrate which is provided with a low emissivity coating comprising:

a) alternating arrangement of n infrared reflective functional layers and n+1 dielectric coatings, where n>1, so that each infrared reflective functional layer is surrounded by dielectric coatings, while the dielectric coating contains one or more dielectric layers, and so that each infrared-reflecting functional layer is protected by a barrier layer directly above and in contact with it, wherein at least one layer, in addition to each infrared-reflecting functional layer and the barrier layer, contains a noble gas, preferably argon,

b) optionally, a protective surface coating, optionally containing one or more dielectric layers,

c) optionally, a seed layer, optionally comprising a dielectric layer under and in contact with at least one infrared reflective functional layer, wherein at least one layer in addition to each infrared reflective functional layer and barrier layer is a dielectric layer of dielectric coating, seed layer and/or protective surface coating, and at the same time the total geometric thickness of the dielectric layers deposited in an atmosphere containing a noble gas is at least 30 nm and not more than 120 nm, and the content of the released noble gas in the calculation on the area of the coated surface of the coated glass panel under pressure less than 10 ^-6 mbar and after heating from room temperature to 460°C in 100 minutes, holding at 460°C for 20 minutes and cooling from 460 to 23°C in 100 minutes is less than 1.5 x 10' ⁶ mbar^cm ³ per mm ² of the coated glass panel; in vacuum insulated glazing.

Many low-e coatings are known in the art. The choice of such a coating depends on a compromise between a variety of properties such as emissivity, light transmission and/or reflection, aesthetic properties (color, haze, etc.), heat treatment resistance, mechanical strength, durability.

The coated glass panel of the present invention must meet the thermal, optical and aesthetic specifications expected of the finished product. Those skilled in the art will know how to produce the desired low emissivity coating having the desired optical and thermal properties. The present invention provides a solution for adjusting these low e coatings so that they are conveniently applied to the VIG assembly. When the coated glass panel according to the present invention is used as part of a VIG package, said package containing the coated glass panel according to the present invention shows high performance in terms of insulating ability. Moreover, it has been found that the excellent thermal performance of a vacuum insulated glazing comprising a coated glass panel of the present invention can be maintained throughout the lifetime of the vacuum insulated glazing despite harsh manufacturing and/or harsh environmental conditions. Additionally, it has been found that the coated glass panel of the present invention provides a very interesting balance between thermal performance and production cost. The performance targets for VIG, expressed in terms of thermal transmittance, U, and the contribution of the low-e coating and its emissivity, ε, are summarized in Table 1. 1.

Table 1

Properties of a VIG Package Containing a Coated Glass Panel According to the Present Invention

Preferably More preferably Most preferably Thermal transmittance, U (W / m ² K) 1.00 0.90 0.80 Issue ability ε 0.07 0.05 0.03

In another aspect of the present invention, the VIG stack may be part of a more complex insulating glass unit (IGU), such as, for example, a triple insulating glass unit in which one or both of the internal spaces between the glass panels are characterized by low pressure. Such a more complex insulating glass unit may contain 2 or more glass panels and may contain a non-glass panel element such as, for example, a polymer film. The IGU may contain more than one low emission coated surface according to the present invention, or may contain another type of coating.

The glass substrate of the coated glass panels according to the present invention may be selected from clear sheet glass, extra clear sheet glass, or colored glass. The term glass in this document refers to any type of glass or equivalent transparent material such as mineral glass or organic glass. The mineral glasses used can be one or more known types of glass such as soda-lime silicate, aluminosilicate or borosilicate, crystalline and polycrystalline glasses. Glass panels can be produced by a float process, a drawing process, a rolling process, or any other known process for making a glass panel, starting from a molten glass composition. Glass panels may optionally have sanded edges. Edge grinding turns sharp edges into smooth edges, which are much safer for people who may come into contact with the glazing vacuum insulating block, in particular the glazing edge. Preferably, the glass panels according to the present invention are soda lime silicate glass, aluminosilicate glass or borosilicate glass panels. Preferably, for reasons of lower manufacturing costs, the glass panels are soda lime silicate glass panels. Typically, the glass panels of the present invention are annealed glass panels.

It should be noted that the invention relates to all possible combinations of features, embodiments and aspects listed in the above description and in the claims.

These and other features and benefits can be better and more fully understood with reference to the following detailed description of exemplary illustrative embodiments in conjunction with the drawings.

Brief description of graphic materials

In FIG. 1 is a graphical representation of the argon concentration in exemplary low emission packages according to example 1 and example 2.

In FIG. 2 is a quantitative graphical representation of the release of argon under vacuum under heating conditions as a function of time for the exemplary low emission packages of Example 1 and Example 2.

In FIG. 3 is a cross-sectional view of a conventional vacuum insulated glass unit.

Description of Embodiments

Definitions.

To maintain consistency, once an example has been identified and numbered (eg example 1), that number will remain attached to that example (this low-e coating) in all paragraphs and tables. Room temperature should be understood as a temperature of 23°. The thermal transmittance, U, is determined according to ISO 19916-1 and is expressed in W/m ² K. The emissivity, ε, was measured according to EN 12898.

In this document, a low-e coating may also be referred to as a low-e package, a layer package, or a package. In this document, the volume of internal vacuum, bounded by the first and second glass panels and a set of separate spacers, and closed by a hermetically bonding seal, in which an absolute vacuum with a pressure of less than 0.1 mbar takes place, is called a vacuum space or a low pressure space/gap, or an evacuated space/low pressure cavity. Residual gas analysis in VIG is performed by Residual Gas Analysis (RGA). The RGA analyzer is a system that allows the extraction of gases contained within the VIG and the measurement of their partial pressures using a highly sensitive quadrupole mass spectrometer. This method is described by N. Ng, R. E. Collins and L. So in Journal of Vacuum Science & Technology A21, 1776 (2003).

The presence of argon in different layers of low-emission packages is determined using X-ray photoelectron spectroscopy (XPS) and X-ray fluorescence spectrometry (XRF). These technical solutions give an image of the elements present in the pavement in direct correlation with the depth in the pavement.

In a general sense, solar control coatings absorb and/or reflect at least some wavelength ranges, which typically results in changes in the optoenergetic properties of the glazing. The materials constituting the individual layers of such a coating are selected depending on the desired final properties of the coated glass panel, and typically include dielectric layers such as oxides, nitrides, carbides, oxynitrides, oxycarbides, metal or silicon oxycarbonitrides, or mixtures of at least two metals, or metal and silicon.

Often used in these dielectric layers are silicon and/or metals such as titanium, zirconium, bismuth, niobium, tin, zinc. The coatings also typically contain layers of metals containing, for example, silver, nickel, chromium, tungsten, gold, palladium, titanium, or mixtures thereof.

- 11 043067

In particular, low-e coating is herein understood to mean any stack of thin layers deposited onto a glass substrate and containing at least one infrared reflective functional layer, such as, for example, silver, gold, palladium, or any metal having infrared reflective properties. radiation, while the specified functional layer is surrounded by dielectric coatings.

The dielectric layer is to be understood as an oxide, nitride, oxynitride of silicon and/or a metal selected from titanium, zinc, tin, zirconium, etc., and a mixture or alloy thereof. Moreover, the dielectric layer is sometimes a mixture of metal oxides. For example, the mixed oxide of tin and zinc may contain zinc and tin in ratios of 10 to 90 wt.% zinc and 90 to 10 wt.% tin. Some layers may be doped to form transparent conductive oxides, such as tin oxide doped with fluorine, indium tin oxide, or zinc oxide doped with aluminium, gallium or boron. The silicon oxide or nitride may contain up to 10% aluminum by weight. Zinc oxide should be understood as an oxide based on zinc as a metal, but this oxide is often alloyed with another metal, such as aluminum.

More generally, the low-e coating of the present invention comprises a first dielectric coating comprising a mixed tin-zinc oxide layer with a thickness of at least 8 nm, preferably 10 nm, more preferably 12 nm and at most 45 nm, preferably 30 nm, more preferably 20 nm. The first dielectric coating may also contain titanium oxide, zirconium oxide or a mixture thereof with a thickness of at least 8 nm, preferably 10 nm, more preferably 12 nm and not more than 45 nm, preferably 35 nm, more preferably 25 nm. A seed layer can be deposited over the first dielectric and directly below the silver layer. This layer has many additional purposes, such as improving the adhesion of the silver layer, improving the quality of the silver layer by reducing its emissivity, and protecting the silver layer. The seed layer is preferably a zinc oxide layer. Under the layer based on zinc oxide, it should be understood that the zinc oxide may contain another metal alloying element, such as, for example, aluminum. When present in the form of a dielectric layer, the thickness of such a seed layer should be taken into account when calculating the total geometric thickness of the dielectric layers deposited in a noble gas atmosphere.

A protective barrier layer is deposited over the silver layer. Preferably, but not limited to, this barrier layer is aluminium-doped zinc oxide, deposited in a known manner from a ceramic target in a 100% argon atmosphere to avoid contamination of the silver layer with oxygen. Alternatively, the barrier layer may be a metal selected from titanium, nickel, chromium, or an alloy containing one of these metals. The barrier layer has a thickness of at least 1 nm, preferably at least 2 nm, more preferably at least 3 nm and at most 12 nm, preferably at most 10 nm, more preferably at most 9 nm. The last dielectric coating over the last silver layer is advantageously a multi-layer coating. The multilayer coating of the latter dielectric coating advantageously comprises one or more of the following layers: zinc oxide layer, mixed tin-zinc oxide layer, silicon nitride layer, titanium-zirconium oxide layer, titanium oxide layer.

General modern methods of magnetron sputtering are well known in the art, and experts are well aware of how to handle them. Mainly, this method involves sputtering the target with an ionized gas selected from argon, krypton, helium, carbon dioxide. The gas may also contain or consist of oxygen or nitrogen as reactive gases if the layer to be deposited is oxide or nitride. The atmosphere is preferably pure argon when necessary to avoid degradation of the metal layer such as, for example, the silver layer or the barrier layer protecting the silver. The choice of argon is due to the fact that it is inert, has sufficient mass and is not too expensive. However, in one aspect, the present invention is directed to a coated glass panel in which typical vapor deposition conditions have been carefully calculated to produce a low-e coating deposited on a glass substrate such that the content of the liberated noble gas, based on the area of the coated surface, in the resultant pressure coated glass panel at 10 ^-6 mbar and after heating from room temperature to 460°C in 100 minutes, holding at 460°C for 20 minutes and cooling from 460 to 23°C in 100 minutes is less than 1.5x10' ⁶ mbar^ ^cm3 per ^mm2 coated glass panel.

The low emissivity coating of the present invention is designed to have specific properties in terms of thermal performance, durability, aesthetic optical properties, and meeting VIG durability requirements. In some embodiments, the low emissivity coatings are also expected to be heat treatable, meaning that they are heat treatable at temperatures up to 650° C. without degrading their properties.

By way of example and without any limitation of the present invention, some glass panels have been made with low emissivity coatings. In table. Figure 2 shows the structure of such low emission packages. As will be discussed below, Example 2 is a counterexample of the present invention.

table 2

Low emissivity coatings used as examples, with thickness in nm given in brackets

Reference Package Description Example 1 ZSO5 (37) / ZnO:AI (5) / Ad (13) / Ti (2) / ZSO5 (45) / ZnO (12) I Ad (13) I Ti (2) IZSO5 (28) 1 TiO ₂ (1 ) Example 2 Comparative example ZSO5 (13) 1 TZO (21) 1 ZnO:AI (6) 1 Ad (10) 1 fiZO (7) 1 ZSO5 (11) /SiN (24)/TZO (6)

ZS05 means a layer of zinc-tin oxide, characterized by the ratio of zinc/tin with 52.4 wt%. zinc. According to embodiments of the present invention, zinc-tin oxides may have zinc/tin weight ratios ranging from 90/10 to 10/90. ZnO:Al is aluminum doped zinc oxide deposited from a doped zinc metal cathode in a reactive sputtering oxygen atmosphere. AZO is aluminum-doped zinc oxide deposited from a ceramic cathode in an inert atmosphere. Regardless of the method of deposition, layers of aluminum doped zinc oxide can be characterized by a percentage of doped aluminum in the range from 2 to 10 at.%. SiN is silicon nitride deposited from a silicon cathode, which is preferably doped with aluminium. TZO is a mixed layer of TiO ₂ and ZrO ₂ oxides in a TiO ₂ /ZrO ₂ weight ratio of 65/35. According to embodiments of the present invention, titanium-zirconium oxides may have TiO ₂ /ZrO ₂ weight ratios ranging from 90/10 to 50/50. Ag is a silver metal layer deposited from an Ag metal cathode, and Ti is a titanium metal layer deposited from a Ti metal cathode. TiO ₂ - a layer of titanium dioxide deposited from a metal cathode of Ti.

Each of the coated glass panels described in Table. 2 was assembled into a VIG assembly with the coated surface facing the inside of the vacuum insulating glass unit. The respective VIG stacks are referred to as VIG Example 1 and VIG Example 2, and are made, respectively, with a single coated glass panel containing the low-e coatings described in Example 1 and Example 2.

An exemplary VIG package (1) shown in FIG. 3 comprises two spaced apart, essentially parallel glass substrates (2), (3) hermetically sealed against one another so that they enclose a low pressure evacuated space/cavity (6) between them. The glass panels or substrates (2), (3) are connected by a peripheral seal (4) at the edges, and between the glass substrates (2), (3) there is an array of load-bearing supports/spacers (5) maintaining the distance between the substrates (2) , (3) VIG-package (1) in view of the presence of space/gap (6) low pressure present between the substrates (2), (3). A low emissivity coating (7) according to the present invention is provided in the interior of a vacuum insulated glass unit. For clarity, the VIG packet shown in FIG. 3 is not shown in real scale.

After assembling the VIGs with the coated glass panel according to Examples 1 and 2, the performance of the resulting VIGs was evaluated by measuring the thermal transmittance and emissivity properties. The results are shown in table. 3.

Table 3

Thermal performance VIG

Example 1 VIG Within the framework of this inventions Example 2 VIG Comparative example U (Bt/m ² K) 0.76 1.5 Emissivity, ε 0.02 0.032

In table. 3 shows the big difference between both low e coatings in terms of thermal performance. VIG assembled with a coated glass panel (VIG Example 1) exhibits a much lower thermal transmittance (U=0.76 W/m ² K) than the Comparative Example (VIG Example 2) which exhibits a higher thermal transmittance (U=1.5

- 13 043067

W / m ² K). Both VIG packets were subjected to a second analysis. Residual gases inside the bags were evacuated and analyzed using the RGA method. The results of these analyzes are shown in table. 4. Gas concentrations are given as ratios to the total amount of gases, i.e. as volumes of specific gases relative to the volume of the entire gaseous medium.

Table 4

Gas analysis with the RGA in VIG assembly

Gas Example 1 VIG Concentration (%) Example 2 VIG - Comparative example Concentration (%) Not 0.49 0.13 n ₂ 82.51 31.19 CH ₄ 1.78 0.68 CnHm <0.01 0.04 Ag 15.21 67.97

A volume fraction of helium less than 0.5% is not significant. From Table. 4 directly shows that in the residual gases present in the vacuum space in the VIG package according to the comparative example, example 2 VIG, after it was closed, a large amount of argon was detected. It has been found that such a large amount of argon can only come from a low-e coating deposited on the glass surface.

In example 1 VIG, the amount of noble gas, mainly argon, in the released gases is much lower, i.e. 15.21% than in the comparative example, VIG example 2, where the amount of argon reaches 67.97%. In example 1 VIG, the gases predominantly contain nitrogen, which is released from the getter under conditions of residual gas analysis (RGA). Nitrogen is not a problem for VIG insulation performance as this gas is captured by the getter. Therefore, the nitrogen detected during the RGA analysis is not taken into account.

Deposition of a low-e coating on a glass substrate with a noble gas, preferably argon, is strongly recommended for reasons of efficiency and production costs. Thus, the present invention is based on an unexpected technical discovery, which is critical to the stability and thermal performance of a glazing, in particular VIG, enclosing at least one coated glass panel, with the coating facing the inside of the glazing, and this coating contains layers that were deposited in a noble gas atmosphere, and which lies in the fact that the amount of noble gas is carefully limited to avoid excessive release during glazing production and/or over time. Moreover, it has been found that the noble gas can be entrapped in the coating during sputtering and then diffuse through this coating at high temperatures and thus be released into the interior of the glazing, in particular into the interior of the vacuum space. It has been further found that not only providing more captured argon by any low e coating, but also the diffusion kinetics of the noble gas through the low e coating is highly dependent on temperature. Therefore, in one embodiment, the present invention relates to a method for depositing a low-e coating on a glass substrate, in which the deposition conditions have been specifically designed to limit the amount of noble gas released into the interior of the glazing, in particular, into the vacuum space, when a coated glass panel is assembled into a glazing, in particular VIG. In another embodiment, the present invention relates to a coated glass panel that has been heat treated at a temperature greater than 300° C. before being assembled into a glazing.

In table. 5(a) and (b) give the stack composition and thickness of the low e coating deposited outward from the glass substrate for Examples 1 and 2, as well as the concentration of the noble gas, argon, present during sputter deposition of the various layers.

In all of the tables below, the infrared reflective functional layer will be referred to as the IR layer.

- 14 043067

Tables 5(a) and (b)

The composition and thicknesses of the low-e coating and the concentration of the noble gas in the deposition atmosphere, starting from the glass substrate

Example 1 Layer Thickness (nm) Concentration noble gas in the sputtering atmosphere, expressed as volume fractions Concentrations of other gases in the atmosphere for sputtering expressed in volume fractions Dielectric coating ZSO5 37 0 100% oxygen ZnO:AI 5 0 100% oxygen IR layer Hell 13 100% argon 0 barrier layer Ti 2 100% argon 0 Dielectric ZSO5 45 0 100% oxygen eskoe coating ZnO:AI 12 0 100% oxygen IR layer Hell 13 100% argon 0 barrier layer Ti 2 100% argon 0 Dielectric coating ZSO5 28 0 100% oxygen _TiO2 1 45% argon 55% oxygen

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Example 2 Comparative Example Layer Thickness (nm) Noble gas concentration in the deposition atmosphere, expressed as a volume fraction Concentrations of other gases in the spray atmosphere, expressed as volume fractions Dielectric coating ZSO5 13 20% argon 80% oxygen TZO 21 90% argon 10% oxygen ZnO:AI 6 20% argon 80% oxygen IR layer Hell 10 100% argon 0 barrier layer AZO 7 100% argon 0 Dielectric coating ZSO5 eleven 20% argon 80% oxygen SiN 24 Minimum Nitrogen quantity argon TZO 6 90% argon 10% oxygen

For SiN (silicon carbide), the sputtering gas is nitrogen and argon, with the nitrogen content adjusted so that SiN is a fully nitrided layer of Si ₃ N 4 . In this example, the amount of argon is approximately 40% of the total volume of gas.

As shown in Table. 5(a) and (b), the inventors have found that when a sputtered low-e coating is deposited with a noble gas present in the sputter gas mixture, the resulting layers are contaminated with said noble gas to an extent that can be critical after VIG assembly. . The inventors have thus found that it is critical to adjust the deposition conditions of the different layers forming the low-e coating in order to obtain a limited amount of released noble gas, in particular a limited amount of released argon, when assembling the corresponding coated glass panel into a VIG package. . This is better shown in Fig. 1, which shows the analysis of XPS in relation to 2 different low-e packages presented in table. 2. This figure shows that the atomic concentration of said noble gas, namely argon, is higher in Example 2, in contrast to the argon concentration of the low-e coating of Example 1, which is less high and relatively constant.

The second analysis, shown in Fig. 2 was performed on the same 2 coated glass panels of the examples (example 1 and example 2) in order to monitor the release of argon when the samples were heated under vacuum. In FIG. 2 shows that the release of argon drops faster to the limit in the sample of example 1, while the other sample (example 2) takes longer to reach the same level. In fact, reaching the indicated argon level takes 2 hours in the case of example 1 and almost 6 hours in the case of example 2. The amount of argon was monitored using a high sensitivity quadrupole mass spectrometer. Thus, in FIG. 2 depicts the release of argon over time when subjected to a temperature profile that mimics the temperature profile of a manufacturing process in a vacuum exhausting step. The coated glass panel was subjected to an increase in temperature to 450°C, a gradual decrease to 400°C, and then maintaining the temperature until degasification began. In FIG. 2 shows that the release of argon over time for the coated glass panel of example 2 is much slower than for the coated glass panel of example 1.

- 16 043067 monitor the total amount of released argon, but also take into account the kinetics of argon diffusion through the low-e coating. In FIG. 2 shows that the coated glass panel of Example 2 takes a much longer time to evacuate argon. Thus, in one embodiment, the present invention is based on the criticality of adjusting the deposition conditions of the different layers forming the low-e coating to obtain a limited amount of noble gas released when the respective coated glass panel is assembled into a VIG stack. In the second embodiment, the present invention is based on the criticality of the noble gas release kinetics, and thus it refers to subjecting the coated glass panel to high temperature for a designated period of time before being assembled into a glazing. A separate heating step avoids an unnecessarily long degassing period during the assembly process of the VIG and thus helps to keep costs reasonable for the production of the respective assembled VIG.

It was decided to characterize the low-e coating of the present invention using a static degassing technique that includes well-defined degassing of the low-e coating and measurement of the gases released using the RGA analysis method. The implemented method is referred to herein as degassable noble gas measurement (ONGM) and is defined below. This method shows that the release of argon is directly related to the amount of argon present in the low e coating and allows characterization of the low e coating of the present invention. To determine the content of liberated argon, a coated glass sample measuring 20 mm x 30 mm was introduced into a hermetically sealed vessel. The vessel was connected to a vacuum pump and the atmosphere of the vessel is vacuum, which was evacuated overnight until a residual pressure of less than 10 ⁻⁶ mbar was reached. The vessel was then completely insulated and subjected to a heating program consistent with the following temperature profile: linear heating from room temperature to 460°C over 100 min, holding at 460°C for 20 min and linear cooling from 460°C to room temperature over 100 min. After completing the degassing protocol, the total amount of degassed compounds was collected, samples were taken and analyzed using a quadrupole mass spectrometer at a temperature equal to 23°C using the known RGA method. The amount of degassed compounds is expressed in mbar cm ³ and is thus a direct indication of the amount of gas present in the sample. This amount (directly proportional to the molar amount of gas) was divided by the total surface area of the sample to be analyzed (expressed in mm) and expressed in mbar^cm ³ per mm ² of the coated glass.

In the ONGM process, two low-e stacks of coated glass panels from Example 1 and Example 2 were provided, and the results are shown in Table 1. 6.

Table 6

Noble gas (argon) measured by the ONGM method in low-emission bags

Plastic bag Amount of noble gas (argon) (mbar.cm ³ /mm ² ) Example 1 ^0.28x10-6 Example 2 2.5χ10-θ

The amount of noble gas in example 2, which is a counterexample, is approximately ten times greater than the amount in example 1, which confirms that this property is an important feature for obtaining effective VIG. It has been found that in order to maintain the performance and stability of an insulating glass unit containing a coated glass panel, the coating comprising layers that have been deposited in a noble gas atmosphere; especially the performance and stability of a VIG containing such a coated glass panel; this amount of noble gas must be carefully limited to avoid excessive and prolonged release over time. Thus, the coated glass panel according to the present invention should represent the content of the liberated noble gas based on the area of the coated surface of the coated glass panel under a pressure of less than 10 ^-6 mbar and after heating from room temperature to 460°C in 100 minutes, keeping at 460° C. for 20 minutes and cooling from 460 to 23° C. in 100 minutes, less than 1.5 x 10' ⁶ mbar-cm ³ per mm ² of the coated glass panel.

To enable deposition using a magnetron sputtering method of a low-e coating that satisfies the noble gas threshold defined by the present invention, various approaches are possible. For the purpose of illustrating the present invention and without limiting it in any way, some adjusted conditions based on a conventional low-e coating are defined below in order to obtain a package that satisfies the present invention.

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In practice, a low-e coating similar to that of example 2 except that the last TZO layer, which can be considered a protective coating layer, was omitted and the package was made using modified sputtering conditions.

Typically, deposition uses vacuum deposition chambers, substrate conveyors, power supplies, and gas locks. Each deposition chamber contains cathodes for magnetron sputtering, inlets for gases, and an outlet for evacuation. Each deposition chamber was characterized by its own atmosphere. The cathodes can be made of metal or ceramic material. The plate glass sheet was washed and introduced into the sputtering device. The glass panel was facing the target, and the mode of operation, such as the required deposition atmosphere, was adjusted in each deposition chamber.

In table. 7 summarizes the sputtering conditions for the examples from Example 2 using the unmodified deposition method and for the new Example 3 using the modified deposition method. In order to produce the special coated glass panel according to the present invention, in addition to removing the protective coating layer, TZO, the conventional sputtering conditions used to produce the coated glass panel of Example 2 were modified as in Example 3. For this method, all chambers for sputtering, the absolute pressure was in the range of 5 to 7 mTorr (6.6 mbar to 9.3 mbar) and the process was carried out at room temperature.

Table 7

Modified and unmodified spray conditions

Layers Target Noble gas volume fraction in sputtering atmosphere(%) Unmodified method (example 2) Modified method (example 3) Dielectric coating ZSO5 ZnSn (52.4% Zn) 20 0 TZO TiZrOx 90 90 ZnO:AI Zn:AI 20 0 IR layer Hell Hell 100 100 barrier layer AZO ZnO:AI 100 100 Dielectric coating ZSO5 ZnSn (52.4% Zn) 20 0 SiN Si: AI Minimum Minimum (ΓΖΟ) TiZrOx 90 Not applicable

ima

In another example, the coated glass panel of Example 2 was heat treated at 480° C. for 8 hours at normal atmospheric pressure. Using this procedure, a new sample was obtained, example 4. The above conditions are only an example. Similar results can be achieved using a lower temperature with longer heat or lower pressure, or both. Alternative conditions are given below in table. 8.

Table 8

Conditions for heat treatment of a low-e coating to remove excess noble gas _________________ gas included in the coating _________________

Temperature (°C) Time (hours) Pressure (mbar) 300-500 1-12 0.1—1000

Each of the coatings that are the results of examples 2-4, analyzed using the ONGM method, and the results are shown in table. 9.

Table 9

The introduction of argon in low-e packages from examples 2-4

Spray conditions Treatment ONGM Ag (mbar.cm ³ /mm ² ) Example 2 Comparative example Unmodified No ^2.5x10-6 Example 3 Modified as indicated in the table 7 No ^0.23x10-6 Example 4 Unmodified Heat treatment at 480 °C for 8 hours at normal atmospheric pressure 0.25x10-6

To confirm that a VIG package assembled using a coated glass panel that meets ONGM specifications will also be able to achieve high thermal performance, with a U value of no more than 1.00 W/ ^m2K , in VIG -package included the coated glass panels of Examples 3 and 4. The resulting VIG packages are named VIG Example 3 and VIG Example 4, respectively. The performance of the resulting VIG packets was evaluated and is shown in Table 1. 10 compared to the counterexample, Example 2 VIG.

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Table 10

Thermal performance VIG

Example 2 VIG Comparative example Example 3 VIG Example 4 VIG and (W / m ² K) 1.5 0.86 0.86 Issue ability 0.032 0.036 0.031

Examples 3 and 4 VIG correspond to the present invention. As indicated in Table 9 above, the argon level measured by the ONGM method for the coated glass panels of Examples 3 and 4 is less than 1.5 x 10' ⁶ mbar^cm ³ /mm ² or even less than 1.0 x 10' ⁶ mbar^cm ³ /mm ² under specified test conditions. In comparison, the argon level measured by the ONGM method for the comparative coated glass panel of Example 2 is over 1.5 x 10 ⁻⁶ mbar^cm ³ /mm ² of the coated glass panel. The VIG package containing low-e coated glass panels shows satisfactory thermal performance. In contrast, the counterexample, Example 2, which is made from a coated glass panel with too high an argon level, i.e. 2.5 x 10 ^-6 mbar·cm ³ /mm ² as shown does not pass the insulation test and will not be taken into account in view of its insulation performance. Moreover, the thermal performance of an insulating glass unit is analyzed by calculating the thermal transmittance, U, which takes into account the phenomena of conduction, convection and radiation in an insulating glass unit. The presence of a low emissivity coating in an insulating glass unit makes it possible to reduce the contribution of radiation to the thermal transmittance and is measured by emissivity. Moreover, in Table. 10 shows that despite similar emissivity performance of the 3 low e coatings tested, the thermal performance of Example 2 VIG is extremely high. Such unsatisfactory thermal characteristics are caused by the presence of a noble gas in the vacuum space, which significantly increases the contribution of convection to the thermal transmittance. The tables below provide additional examples of compositions and spray conditions for coated glass panels according to the present invention (Example 5 and Example 6)._______________

EXAMPLE 5 Layers Target Thickness (nm) The composition of the gas in the atmosphere for spraying (%) From glass substrate: ZSO5 ZnSn (52.4% Zn) 18 100% oxygen TZO TiZrOx 22 90% argon and 10% oxygen ZnO:AI Zn:AI 5 100% oxygen Hell Ag 13 100% argon AZO ZnO:AI 5 100% argon ZSO5 ZnSn (52.4% Zn) 18 100% oxygen SiN Si: AI 24 40% argon and 60% nitrogen EXAMPLE 6 Layers Target Thickness (nm) Gas composition in atmosphere for spraying (%) From glass substrate: ZSO5 ZnSn (52.4% Zn) 35 100% oxygen

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ZnO:AI Zn:AI 5 100% oxygen Hell Ag 13 100% argon AZO ZnO:AI 5 100% argon ZSO5 ZnSn (52.4% Zn) 4 100% oxygen SiN Si:AI 6 40% argon and 60% nitrogen SiN Si:Al 18 40% argon and 60% nitrogen ZSO5 ZnSn (52.4% Zn) 10 100% oxygen TZO TiZrOx 3 100% oxygen ΖηΟ:ΑΙ ZN:AI 5 100% oxygen Hell Ag 14 100% argon AZO ZNO:AI 8 100% argon ZSO5 ZnSn (52.4% Zn) 8 100% oxygen SiN Si:AI 25 40% argon and 60% nitrogen

CLAIM

Claims (18)

1) so that each infrared-reflecting functional layer is surrounded by dielectric coatings, wherein the dielectric coating contains one or more dielectric layers, and 1. Coated glass panel, which contains a glass substrate provided with a low-emissivity coating containing: a) alternating arrangement of n infrared reflective functional layers and n+1 dielectric coatings, where n>1, 2. The coated glass panel of claim 1, further comprising: b) a protective surface coating, optionally containing one or more dielectric layers; and/or c) a seed layer, optionally comprising a dielectric layer under and in contact with the at least one infrared reflective functional layer. 2) so that each infrared reflective functional layer is protected by a barrier layer directly above and in contact with it, wherein at least one layer in addition to each infrared reflective functional layer and the barrier layer contains a noble gas, while at least one the layer in addition to each infrared reflective functional layer and the barrier layer is a dielectric layer of a dielectric coating, a seed layer and/or a protective surface coating, and the total geometric thickness of the dielectric layers deposited in a noble gas atmosphere is at least 30 nm and not more than 120 nm; and at the same time, the content of the released noble gas based on the area of the coated surface of the coated glass panel under pressure is less than 10 ^-6 mbar and after heating from room temperature to 460°C for 100 minutes, holding at 460°C for 20 minutes and cooling 460 to 23°C in 100 minutes is less than 1.5 x 10' ⁶ mbar^cm ³ per mm ² coated glass panel. 3. Coated glass panel according to any one of the preceding claims, characterized in that the noble gas is argon. 4. The coated glass panel according to any one of the preceding claims, characterized in that the content of the released noble gas, based on the area of the coated surface of the coated glass panel under pressure, is less than 10 ^-6 mbar and after heating from room temperature - - 21 043067 heating up to 460°C in 100 min, holding at 460°C for 20 min and cooling from 460 to 23°C in 100 min is less than 1.0x10-6 mbar-cm ³ per mm ^{2 of} coated glass, preferably less than 0.5x10-6 mbar-cm ³ per mm ² of coated glass panel. 5. Coated glass panel according to any one of the preceding claims, characterized in that the total geometric thickness of the dielectric layers deposited in the noble gas atmosphere is at least 45 nm, alternatively at least 60 nm. 6. Coated glass panel according to any one of the preceding claims, characterized in that the geometric thickness of the low-e coating is in the range of 70 to 300 nm, preferably 80 to 250 nm, and most preferably 90 to 190 nm. 7. Coated glass panel according to any one of the preceding claims, characterized in that the infrared reflective functional layer(s) comprises or consists of silver. 8. Coated glass panel according to any one of the preceding claims, characterized in that the low-e coating comprises, from the glass substrate to the outside: a) a mixed tin-zinc oxide layer; b) a layer based on zinc oxide; c) a layer of silver; d) barrier layer; f) dielectric coating. 9. A coated glass panel according to any one of the preceding claims, characterized in that the low-e coating comprises, from the glass substrate to the outside: a) a dielectric coating containing a mixed tin-zinc oxide layer; b) a seed layer containing a layer based on zinc oxide; c) an infrared reflective silver functional layer; d) barrier layer; f) dielectric coating; f) zinc oxide layer; g) a second infrared reflective silver functional layer; h) a second barrier layer; i) dielectric coating. 10. Coated glass panel according to any one of the preceding paragraphs, characterized in that at least one barrier layer is a metal, its oxide or nitride; wherein the metal is selected from the list consisting of titanium, zinc, nickel, chromium, or any alloy containing one of these metals, and in particular zinc oxide. 11. Coated glass panel according to any of the preceding claims, characterized in that at least one dielectric coating is a coating of one or more dielectric layers containing any of the oxide or nitride of titanium, silicon, zinc, tin, zirconium, or mixtures thereof . 12. A coated glass panel according to any one of the preceding claims, characterized in that the total thickness of the dielectric layers deposited in an atmosphere containing a noble gas, preferably argon, is at most 100 nm, preferably at most 90 nm. 13. A method for producing a coated glass panel according to any one of the preceding claims, which comprises delivering the glass substrate to a magnetron sputtering facility and depositing layers of predetermined thickness on the glass substrate by means of reduced pressure cathode sputtering, and which is characterized in that i) the IR-only functional layer and the barrier layer are deposited in an atmosphere containing 95 to 100% noble gas, preferably argon; ii) metal oxide dielectric layers from metal targets are deposited in an atmosphere containing 95 to 100% oxygen; iii) the other dielectric layers are deposited in such an atmosphere that the volume fraction of the noble gas in the gaseous medium does not exceed 90%. 14. A method for producing a coated glass panel according to any one of claims 1 to 12, characterized in that said coated glass panel is subjected to heat treatment at a temperature of more than 300°C, preferably 400°C and more preferably 480°C. 15. Process according to claim 14, characterized in that the heat treatment is carried out at a pressure less than or equal to 1 bar, preferably less than or equal to 10 mbar, more preferably less than or equal to 1 mbar and most preferably less than or equal to 0.1 mbar. 16. Method according to any one of claims 14, 15, characterized in that the heating time is at least 0.5 hours, preferably at least 2 hours and more preferably at least 6 hours. 17. Vacuum insulated glass unit comprising at least one coated glass panel according to any one of the previous claims 1-12. 18. Vacuum insulated glass unit according to claim 17, characterized in that the U value is not more than 1.00 W/m ² K, more preferably not more than 0.90 W/m ² K, and most preferably not more than 0.80 W / m ² K.