Technical Field

The present disclosure relates, in general to a glazing comprising a transparent substrate, on the surface of which a stack of thin layers is deposited which comprises two functional layers based on silver making it possible to act on the solar and/or infrared radiation likely to strike said surface. More specifically the invention relates to a glazing having an absorber layer comprised in the stack of thin layers for achieving low internal reflection and a wide range of external reflection colors while maintaining good selectivity.

Background

Solar control glass has a large part to play in the future of construction, as external temperatures will continue to rise and so will the expectations of comfort. Legal agreements and devices aimed at reducing the environmental impacts of human activities are increasing on regional, national and international scales. These agreements and arrangements aim in particular to reduce the energy consumption of infrastructure. They recommend or oblige in particular the equipment of buildings and transport vehicles so as to reduce the energy consumption of their air conditioning and heating means.

Solar control coatings comprise a plurality of stacks that are optimized for desired specific requirements based on geography and/or aesthetics and/or optical behavior and/or durability and/or functionality. Conventionally, to improve the solar control properties, the thickness of the metallic layers in the stack can be increased. But, this essentially increases the internal and external light reflections on the coating side and glass side, respectively. However, a low internal reflection is desirable to enables a clear view of the outside to a viewer positioned inside the building. Further, for a solar control glass, it is sometimes desirable to have an aesthetic pleasing appearance on the interior and the exterior reflection.

In certain situations, designers of coated articles strive for a combination of desirable visible transmission, desirable color, low internal reflection, low sheet resistance (Rs) and good selectivity. All these properties along with the choice of external reflection colors. Low sheet resistance characteristics permit such coated articles to block significant amounts of IR radiation so as to reduce for example undesirable heating of vehicle or building interiors. Low internal reflection provides visual comfort for viewers inside the building and higher the selectivity of a functionalized glazed, higher is its thermal performance, ideally without prejudice to the light transmission in the visible spectrum.

Solutions have already been proposed to meet the objective of combined desired performance, optical and aesthetic properties. In Patent FR-2751 666 it is proposed to insert, between the glass and the first dielectric layer, an absorbent layer based on iron oxide. In Patent FR-2 708 262 it is proposed to insert an absorbent layer of the titanium nitride type, in contact with and above the silver layer. However, these solutions have a drawback in both cases if the stack of thin layers undergoes a heat treatment of the annealing, bending or toughening type: the absorbent layer will be significantly changed optically and/or make the multilayer stack in its entirety change optically. Similar solutions are also found in Patent Application US 2008070044 and Patent US 729440 which suffer from the above mentioned drawback.

In Patent US 11027527 and Patent US 10947153 it is proposed to add an absorber layer that is either partially oxidized or partially nitrided for increasing durability and obtaining desirable external reflection colors viz., grey or silver, low visible transmission, desirable external reflectance values, desirable transmission color and more desirable internal reflective b* values, low SF and SHGC value(s). Here the absorber layer is proposed to be inserted between the first and second functional layers based on silver. However, these solutions have a drawback in both cases of having high sheet resistance values viz., <6 ohm/sq and <7 ohm/sq, respectively. Furthermore, these solutions achieve low light transmission values ranging between 23 to 43% and 20 to 45%, respectively.

Likewise, in Patent US 7166360 the absorber layer is inserted between the first and second functional layers based on silver to adjust the light transmission level of glazing without correspondingly increasing too significantly the level of external light reflection. However, the internal reflection of this invention would be significantly high which could be attributed to the thick second functional silver layer and thin first functional silver layer.

The patent US 7648769 proposes a low-E coating with absorbing layer designed for achieving bluish color at off-axis viewing angles. The patent document focusses on obtaining a particular aesthetic appearance on the external reflection and has a high internal reflection in IGU configuration. For a light transmission between 46-54% the internal reflection is in the range of 17-28% and for a light transmission between 56-68%, the internal reflection is in the range of 13 to 23%. Thus internal reflection of the disclosed coated article is generally high and embodiments with low internal reflection have rather high light transmission.

Thus it has been difficult to achieve desirable light transmission and good selectivity in combination with low internal reflection, desirable external reflective coloration, acceptable solar values such as low sheet resistance, solar factor (SF) and/or solar heat gain coefficient (SHGC). While low SF and SHGC values are indicative of good solar protection against undesirable heating of rooms or the like protected by windows/ glazings, the achievement of lower SF values may come at the expense of sacrificing coloration. This additionally makes it difficult to achieve desired aesthetic characteristics alongside solar performance characteristics. Hence there is room for improvement in solar control coatings comprised with absorbent layer with respect to one or more of durability, visible transmission, coloration, selectivity and/or internal reflectance.

The objective of the invention is therefore to develop a glazing having: low internal reflection while maintaining good selectivity and desirable light transmission exceptional solar control properties and enhanced aesthetic appearance; capable of heat treatment without losing the solar control and aesthetic properties; low sheet resistance; and - wide range of external reflective colorations ranging from blue to neutral alongside all the above mentioned objectives.

The complexity of the stacks comprising two silver-based functional layers makes it difficult to improve the thermal performance and reflection properties without adversely affecting the other properties of the stack. The Applicant has surprisingly discovered that by optimizing the thicknesses of the two metallic functional layers, inserting a thin absorbent layer between the two metallic functional layers and having metal oxide dielectric layers (particularly zinc oxide), a layer stack capable of exhibiting the desired properties is obtained. The solution of the invention represents an excellent compromise between the optical performance, thermal performance, transparency and aesthetic appearance.

It is thus a purpose of this disclosure to help achieve all the said characteristics, detail of which will become apparent to the skilled artisan once given the following disclosure.

Certain example embodiments of this disclosure relate to a glazing that has visible light transmission of 49%; internal reflection of 14%; external reflection of 18% and a solar factor of 0.26. The glazing exhibits a blue coloration in external reflection and green in internal reflective coloration.

Certain other example embodiments of this disclosure relate to a glazing that has visible light transmission of 46%; internal reflection of 12%; external reflection of 19% and a solar factor of 0.27. The glazing exhibits a neutral coloration in external reflection and green in internal reflective coloration

In all embodiments of the present invention, the glazing is durable having an increased thermal stability and mechanical performance while retaining desired optical characteristics of the article.

Summary of the Disclosure

In one aspect of the present disclosure, a glazing comprising a transparent substrate with a stack of thin layers is provided. The first and second functional layers are provided to have reflection properties in the infrared and/or solar radiation range. A first, second and third dielectric coatings each comprising two or more dielectric layers are provided. Each dielectric layer independently comprises a dielectric material. Each functional layer is sandwiched between two dielectric coatings. At least one absorbent layer that absorbs visible light comprising niobium is located in the second dielectric coating such that the absorbent layer is in contact and in between two dielectric layers of the second dielectric coating. It is characterized in that, the ratio of thickness of the first functional layer comprising silver or an alloy of silver to the thickness of the second functional layer comprising silver or an alloy of silver ranges between 0.75 to 1.5 in order for the glazing to have a visible transmission between 45% and 60%.

In one other aspect of the present disclosure, a glazing comprising a transparent substrate with a stack of thin layers having internal reflection less than 17% is provided. The stack of thin layers further achieves a wide range of external reflective colorations. The first and second functional layers are provided to have reflection properties in the infrared and/or solar radiation range. A first, second and third dielectric coatings each comprising two or more dielectric layers are provided. Each dielectric layer independently comprises a dielectric material. Each functional layer is sandwiched between two dielectric coatings. At least one absorbent layer that absorbs visible light comprising niobium is located in the second dielectric coating such that the absorbent layer is in contact and in between two dielectric layers of the second dielectric coating. It is characterized in that, the ratio of thickness of the first functional layer comprising silver or an alloy of silver to the thickness of the second functional layer comprising silver or an alloy of silver ranges between 0.75 to 1.5 in order for the glazing to have a visible transmission between 45% and 60%.

In yet another aspect of the present disclosure, a glazing comprising a transparent substrate with a stack of thin layers having internal reflection less than 17% is provided. The stack of thin layers further achieves a wide range of external reflective colorations. The stack of thin layers comprises: first and second functional layers reflecting infrared and/or solar radiation comprising silver or an alloy of silver, the first functional layer located closer to the transparent substrate than the second functional layer; first dielectric coating comprising two or more dielectric layers located below the first functional layer; a first lower barrier layer comprising Ni and Cr location below and directly contacting the first functional layer; a first upper barrier layer comprising Ni and Cr located over and directly contacting the first functional layer; second dielectric coating comprising two or more dielectric layers located above the first functional layer; at least one absorbing layer that absorbs visible light comprising niobium located in the second dielectric coating such that the absorbent layer is in contact and in between two dielectric layers of the second dielectric coating; a second lower barrier layer comprising Ni and Cr location below and directly contacting the second functional layer; a second upper barrier layer comprising Ni and Cr located over and directly contacting the second functional layer; third dielectric coating comprising two or more dielectric layers located above the second functional layer; and optionally further comprising an overcoat layer comprising titanium oxide or titanium zirconium oxide or carbonover and directly contacting the dielectric layer comprising aluminum nitride or silicon nitride. It is characterized in that, the ratio of thickness of the first functional layer comprising silver or an alloy of silver to the thickness of the second functional layer comprising silver or an alloy of silver ranges between 0.75 to 1.5 in order for the glazing to have a visible transmission between 45% and 60%.

Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

Brief Description of the Drawings

Embodiments are illustrated by way of example and are not limited to those shown in the accompanying figures.

FIG. 1 illustrates a stack of thin layers deposited on a transparent glass substrate, according to one embodiment of the present disclosure;

FIG. 2 illustrates a stack of thin layers deposited on a transparent glass substrate, according to one other embodiment of the present disclosure; and

FIG. 3 illustrates a stack of thin layers deposited on a transparent glass substrate, according to yet another embodiment of the present disclosure.

Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the invention.

Detailed Description

Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or similar parts. Embodiments disclosed herein are related to a solar control glass article comprising an absorber layer sandwiched in between two silver layers to enable low internal reflection (on the coating side) alongside a wide range of external reflective colorations (on the glass side) ranging from blue to neutral, while the said coating is on the side of the glass facing the inside of the building. Further the solar control glass article exhibits a high thermal performance, good selectivity and improved aesthetics for use in the context of insulating glass (IG) window units, vehicle windows, other types of windows, or in any other suitable application.

A coated solar control glass article 101 as illustrated in FIG. 1, is disclosed in various embodiments of the invention. FIG. 1 illustrates a structure of a stack of thin layer having two functional metallic layers 50, 150 deposited on a transparent substrate 10. Each of the metallic functional layers 50, 150 is positioned between dielectric coatings 20 (first dielectric coating), 40 (second dielectric coating), 60 (third dielectric coating) such that: the first functional layer 50, starting from the substrate, is positioned between the dielectric coatings 20, 40 and the second functional layer 150 is positioned between the dielectric coatings 40, 60. The dielectric coatings 20, 40, 60, each include at least two dielectric layers viz., 21, 22; 41, 43; 61, 62. Each dielectric layer includes a dielectric material. The two functional metallic layers 50, 150, each comprise a noble material which preferably is silver or an alloy of silver. An absorber layer 100 is disposed in between the dielectric layer 41 and the dielectric layer 43 of the second dielectric coating 40. In other words, the second dielectric coating 40 includes an absorber layer 100 which is sandwiched by the dielectric layer 41 and the dielectric layer 43.

Thus the stack of thin layers deposited on the transparent substrate 10 comprises moving away from the transparent substrate 10 outwardly the following layers: 21/ 22/ 50/ 41/ 100/ 43/ 150/ 61/ 62. The layers 21, 22, 50 ,41, 100, 43, 150, 61 and 62 are deposited through magnetron sputtering or other types of sputtering or other suitable deposition techniques. Other layers may be provided between illustrated layers in certain other embodiments of the present disclosure as shown in FIG. 2. In alternative embodiments of the present disclosure, certain illustrated layers may be absent. Thus, for example, the stack of thin layers thereof shown in FIG. 1 are considered to be "on" the substrate 10 even when other layer(s) (not shown) are provided there between.

The stack of thin layers may further comprise as shown in FIG. 2 barrier layers 31, 91 deposited as under layers in contact with the functional layers 50 or 150, respectively; barrier layers 32, 92 deposited as over layers in contact with the functional layers 50 or 150, respectively and at least one overcoat layer 200. In an alternate embodiment the stack of thin layers comprise more than one barrier layers deposited as under layers in contact with the functional layer; and/ or more than one barrier layers deposited as over layers in contact with the functional layer.

The presence of two metallic functional layers 50, 150 makes the solar control glass article 101 highly reflective and hence the absorber layer 100 is inserted between the two metallic functional layers 50, 150 to control reflection values. By adjusting the thicknesses of the functional layers 50, 150 and maintaining the ratio of thickness of the first functional layer 50 comprising silver or an alloy of silver to the thickness of the second functional layer 150 comprising silver or an alloy of silver between 0.75 to 1.5 the transparency of the solar control glass article 101 may be controlled so as to obtain light transmission TL between 45% and 60%. This range is particularly suitable for glazings intended to be used in high-sunshine regions. But the major advantage of the invention is that of achieving the satisfactory visual appearance while reducing the internal reflection values to as low as less than 17% and being able to vary the external reflective coloration from blue to neutral and still retaining low sheet resistance and good selectivity. This is attributable to the insertion of the thin absorber layer 100 chosen from a transition metal containing material which preferably includes a niobium containing material. More particularly significant is all these properties do not take place to the detriment of the solar protection performance. The excellent energy performance is maintained without requiring substantial modifications of the other parameters of the stack such as the nature, the thickness and the sequence of the layers forming it.

Within the meaning of the present invention, the label “first”, “second”, “third” for the functional layers and/ or dielectric coatings are defined starting from the substrate bearing the stack and with reference to the layers or coatings having the same function. For example, the functional layer closest to the substrate is the first functional layer, the next one moving away from the substrate is the second functional layer. Likewise, the dielectric coating closest to the substrate is the first dielectric coating, the next one moving away from the substrate is the second dielectric coating etc. Thicknesses stated in the present document with no other specifications are physical, real or geometric thicknesses and are expressed in nanometers (and not optical thicknesses). The thickness of the dielectric coatings is represented as T. Tl, T2 and T3 according to the specific dielectric coating they refer to.

According to one embodiment of the present invention, the two functional metallic layers 50, 150 satisfy the condition: the ratio of the thickness of first functional layer 50 to the thickness of the second functional layer 150 ranges between 0.75 to 1.5, inclusive of the said value. The thickness of the first and second functional layers 50, 150 ranges between 8 and 16 nm. These thickness ranges for the functional metallic layers 50, 150 are the ranges for which the best results are obtained for a light transmission between 45% and 60%, internal reflection as low as less than 17%, external reflection less than 24% and external reflection color values: a*g between -5 to -1 & b*g between -20 and -1 in combination with selectivity values greater than 1.7 and solar factor less than 0.35.

The role of the barrier layers 32, 92 deposited over the functional layers is conventionally to protect the layers underneath from a possible degradation during the deposition of the upper dielectric coating and during an optional high-temperature heat treatment of the annealing, bending and/or tempering type. Whereas, the role of barrier layer 31, 91 below the functional layer is to promote adhesion and improve the mechanical durability during transport and processing. The barrier layers are selected from metallic layers based on a metal or on a metal alloy, metal nitride layers and metal oxide layers of one or more elements selected from NiCr or NiCrOx, NiCrN _x . When these barrier layers are deposited in metallic, nitride or oxide form, these layers may undergo a partial or complete oxidation depending on their thickness and the nature of the layers that surround them, for example, at the time of the deposition of the next layer or by oxidation in contact with the underlying layer. In alternative embodiments of the present invention, at least one of the functional layer 50 or 150 is sandwiched within barriers layers comprised of Ni and Cr. In further alternative embodiments, either one or both the functional layers 50, 150 have either the underlying barrier layers 31, 91 or the overlying barrier layers 32, 92.

According to one embodiment of the present invention, the barrier layers 31, 91, 32, 92 satisfy the condition: each functional metallic layer is in contact with at least one barrier layer selected from a barrier under layer and a barrier over layer, and/or each functional metallic layer is in contact with a barrier under layer and a barrier over layer, and/or the thickness of each barrier layer ranges between 0.5 nm and 4 nm.

In all embodiments of the present invention, the absorber layer 100 is inserted in the second dielectric coating 40 and is chosen from a transition metal containing material which preferably includes a niobium containing material. The niobium containing material is preferably nitrided, oxy-nitrided or partially oxidized. The niobium containing material is specifically partially oxidized in exemplary embodiments. In many embodiments, the fully oxidized niobium is not desired. Thickness of the absorbent layer 100 is in the range of 0.5 nm and 3 nm. While the absorber layer is not restricted to Nb containing material, similar materials performing in a similar manner to substantially result in similar or substantially similar properties when used in the specifically claimed stack is considered to also fall within the scope of the invention. The position of the absorber layer between the first and second functional layer provides for a better control over reflection values both in the external glass side and the internal coating side. Further this configuration of the absorber layer provides for achieving a wide range of reflection colors while maintaining the desired levels of reflection.

According to another embodiment, the dielectric coatings 20, 40, 60 satisfy the condition: the dielectric coatings 20, 40 and 60 each have a thickness Tl, T2 and T3, wherein the thickness T1 of the dielectric coating 20 ranges between 5 to 50 nm and/or thickness T2 of the dielectric coating 40 ranges between 20 to 120 nm and/or thickness T3 of the dielectric coating 60 ranges between 10 to 50 nm, inclusive of all said values mentioned for TI, T2 and T3. Each of the three dielectric coatings 20, 40, 60 comprise at least one dielectric layer comprising one of the metallic nitride materials, aluminum nitride or silicon nitride. In a preferred embodiment the dielectric material is silicon nitride. In some embodiments of the present invention, each of the three dielectric coatings 20, 40, 60 comprise at least one dielectric layer comprising a metal oxide dielectric material. In a preferred embodiment the second dielectric coating 40 comprise at least two dielectric layers comprising a metal oxide dielectric material. In all embodiments of the present invention, the metal oxide dielectric material is selected from a group consisting of zinc oxide, tin oxide, niobium oxide, silicon dioxide, titanium oxide, aluminium oxide, zirconium oxide or their combinations thereof. In a preferred embodiment the metal oxide dielectric material is zinc oxide. In some embodiments of the present invention, each of the three dielectric coatings 20, 40, 60 comprise at least two dielectric layers each viz., 21, 22; 41, 43 and 61, 62 as shown in FIG. 1. In still further embodiment, each of the three dielectric coatings 20, 40, 60 comprise at least one dielectric layer comprising one of the metallic nitride materials, aluminum nitride or silicon nitride and at least one other dielectric layer comprising a metal oxide dielectric material.

In various embodiments, for instance the first dielectric coating 20 includes a dielectric layer 21 made of a metallic nitride material which includes one of an aluminum nitride or silicon nitride and another dielectric layer 22 made of a metal oxide material. Likewise, the third dielectric coating 60 includes a dielectric layer 61 made of a metallic nitride material which includes one of an aluminum nitride or silicon nitride and another dielectric layer 62 made of a metal oxide material.

In multiple embodiments of the present invention, the second dielectric coating 40 comprises at least three dielectric layers viz., 41, 42 and 43. In still further multiple alternate embodiments, the second dielectric coating 40 comprises at least four dielectric layers viz., 41, 42, 43 and 44 or at least five dielectric layers viz., 41, 42, 43, 44 and 45 as shown in FIG. 3. The second dielectric coating 40 comprises at least one dielectric layer placed below the absorbent layer 100 and at least two dielectric layers placed above the absorbent layer 100. According to preferred embodiments, the dielectric layers placed in the immediate vicinity of the absorbent layer 100 both above and below comprise of a metallic nitride material which includes one of an aluminum nitride or silicon nitride. The dielectric layers comprising a metal oxide material are generally placed both above and below the absorbent layer 100 but not in the immediate vicinity of the absorber layer 100. Thus the absorbent layer 100 is sandwiched between one or more dielectric layers of the second dielectric coating 40. In preferred embodiments of the present invention, the thickness of the one or more dielectric layers placed below the absorbent layer 100 ranges between 5 to 40 nm while the thickness of the one or more dielectric layers placed above the absorbent layer 100 ranges between 25 to 80 nm. In a preferred embodiment, the absorbent layer 100 is sandwiched by at least two dielectric layers 41, 42 below it and at least two dielectric layers 43, 44 above it.

In all embodiments of the present invention, the dielectric layers of first, second and third dielectric coatings 20, 40, 60 comprising a metal oxide material are separated from the first and second functional layers 50, 150 and separated from the absorber layer 100.

In all embodiments of the present invention, the absorbent layer 100 is sandwiched between two dielectric layers of the second dielectric coating 40 in immediate vicinity comprising metallic nitride material which includes one of an aluminum nitride or silicon nitride. In a preferred embodiment, the absorbent layer 100 is sandwiched between two dielectric layers made of silicon nitride.

According to preferred embodiments of the present invention, the first dielectric coating 20 comprising the dielectric layers 21, 22 is positioned below the first functional metallic layer 50; the dielectric layer 21 has a barrier function and is based on most preferably silicon nitride optionally doped with zirconium; the dielectric layer 22 has a stabilizing function and is based on most preferably crystalline oxide in particular zinc oxide.

According to preferred embodiments of the present invention, the third dielectric coating 60 comprising the dielectric layers 61, 22 is positioned above the second functional metallic layer 150; the dielectric layer 62 has a barrier function and is based on most preferably silicon nitride optionally doped with zirconium; the dielectric layer 61 has a stabilizing function and is based on most preferably crystalline oxide in particular zinc oxide.

According to preferred embodiments of the present invention, the second dielectric coating 40 comprises dielectric layers 41, 42, 43, 44, 45 all dielectric layers are positioned below the second metallic functional layer 150. The dielectric coating 40 comprises at least one dielectric layer having a barrier function; and/or at least two dielectric layers having a stabilizing function; and/or at least one dielectric layer having a smoothing function. According to this embodiment, the dielectric layers 41, 45 are dielectric layers having a stabilizing function and is based most preferably on crystalline oxide in particular zinc oxide. According to this embodiment, the dielectric layer 42, 43 are dielectric layers having a barrier function and is based most preferably on silicon nitride. According to this embodiment, the dielectric layer 44 is the dielectric layer having a smoothing function and is based on a mixed oxide of at least two metals selected from Sn, Zn, In, Ga, preferably zinc tin mixed oxide layers which are optionally doped. The dielectric layer 44 having a smoothing function, if present is generally sandwiched between at least one dielectric layer having a barrier function and at least one dielectric layer having a stabilizing function, preferably with the at least one dielectric layer having a barrier function positioned below the dielectric layer having a smoothing function and the at least one dielectric layer having a stabilizing function positioned above the dielectric layer having a smoothing function.

Dielectric layer having a barrier function according to the present invention should be understood as a layer made of a material capable of forming a barrier to the diffusion of sodium, oxygen and/or water at high temperature, originating from either the transparent substrate or the ambient atmosphere towards the functional layer. The constituent materials of the dielectric layer having a barrier function thus must not undergo chemical or structural modification at high temperature which would result in a modification to their optical properties. The layer or layers having a barrier function are preferably also selected from a material capable of forming a barrier to the constituent material of the functional layer. The dielectric layers having a barrier function thus allow the stack to be subjected to heat treatments of the annealing, tempering or bending type, without excessively significant optical change.

Dielectric layer having a stabilizing function according to the present invention should be understood as a layer selected so as to stabilize the interface between the functional layer and this layer. This stabilization results in the reinforcing of the adhesion of the functional layer to the layers which surround it and thus it will oppose the migration of its constituent material. This in turn results in improved deposition of functional layers. The dielectric layer(s) having a stabilizing function may be directly in contact with a functional layer or separated by a barrier layer and directly influence performance values such as SF and U values.

Preferably, the final dielectric layer of each dielectric coating located underneath a functional layer is a dielectric layer having a stabilizing function. This is because it is advantageous to have a layer having a stabilizing function, for example, based on zinc oxide underneath a functional layer, as it facilitates the adhesion and the crystallization of the silver-based functional layer and increases its quality and its stability at high temperature. It is also advantageous to have a layer having a stabilizing function, for example, based on zinc oxide on top of a functional layer, in order to increase the adhesion thereof and to optimally oppose the diffusion from the side of the stack opposite the substrate. The dielectric layer(s) having a stabilizing function may thus be on top of and/or underneath at least one functional layer or each functional layer, either directly in contact therewith or separated by a barrier layer.

Advantageously, each dielectric layer having a barrier function is separated from a functional layer by at least one dielectric layer having a stabilizing function.

Dielectric layer having a smoothing function according to the present invention should be understood as a layer having the role of promoting the growth of the stabilizing layer in a preferential crystallographic orientation, which promotes the crystallization of the silver layer via epitaxial phenomena. The smoothing layer is located underneath and preferably in contact with a stabilizing layer. The smoothing layer based on a mixed oxide may be described as “noncrystalline” in the sense that it may be completely amorphous or partially amorphous and thus partially crystalline, but it cannot be completely crystalline over its entire thickness. It cannot be of metallic nature since it is based on a mixed oxide (a mixed oxide is an oxide of at least two elements).

According to an optional embodiment of the present invention, the stack of thin layers comprises at least one overcoat layer 200 deposited farthest from the surface capable of being in contact with the atmosphere based on titanium zirconium nitride or oxynitride, titanium zirconium oxide or titanium oxide. According to another optional embodiment of the present invention, the stack of thin layers comprises at least two overcoat layers disposed farthest from the surface capable of being in contact with the atmosphere one layer based on titanium zirconium nitride or oxynitride, titanium zirconium oxide or titanium oxide and another layer based on Carbon. The overcoat layer generally has a thickness of less than 5 nm, more preferably less than 4 nm.

In a still further alternative embodiment, the solar control glass article 101 is provided with a temporary protective coating conventionally known in the art in order as the furthest layer from the substrate to protect the underlying stack of thin layers during heat treatment. As is known from the conventional processes this temporary protective layer is burned off during the heat treatment.

According to a particular exemplary embodiment of the present invention, a coated solar control glass article 101 having the stack of thin layers comprises starting from the glass substrate 10, as illustrated in FIG. 3: a first dielectric coating 20 comprising at least one dielectric layer having a barrier function 21 and one dielectric layer having a stabilizing function 22; optionally a barrier layer 31; a first functional layer 50; optionally a barrier layer 32; a second dielectric coating 40 comprising at least two lower dielectric layers one having a stabilizing function 41 and another having a barrier function 42; at least three upper dielectric layers, one of them having a barrier function 43, another having a smoothing function 44 and another having a stabilizing function 45; an absorber layer 100 sandwiched between the dielectric layers 42 and 43 of the second dielectric coating 40; optionally a barrier layer 91; a second functional layer 150; optionally a barrier layer 92; a third dielectric coating 60 comprising at least one lower dielectric layer having a stabilizing function 61 and one upper dielectric layer having a barrier function 62; and optionally one overcoat layer 200.

The transparent substrates according to the present invention are preferably made of an inorganic rigid material, such as glass, or an organic material based on polymers (or made of polymer). The substrate is preferably a sheet of glass or of glass-ceramic. The substrate is preferably transparent, colorless (it is then a clear or extra-clear glass) or colored, for example colored blue, grey, green or bronze. The glass is preferably of soda-lime-silica type, but it may also be made of glass of borosilicate or alumino-borosilicate type. The substrate advantageously has at least one dimension greater than or equal to 1 m, or even 2 m and even 3 m. The thickness of the substrate generally varies between 0.5 mm and 19 mm, preferably between 0.7 and 9 mm, in particular between 2 and 12 mm, or even between 4 and 10 mm. The substrate may be flat or curved, or even flexible.

The material, that is to say the substrate coated with the stack, may undergo a high-temperature heat treatment such as an annealing, for example a flash annealing such as a laser or flame annealing, a tempering and/or a bending. The temperature of the heat treatment is greater than 500° C, preferably greater than 550° C, and better still greater than 600° C. The substrate coated with the stack may therefore be curved and/or tempered.

The invention also relates to a glazing comprising a material according to the invention. Conventionally, the faces of a glazing are denoted starting from the outside of the building and by numbering the faces of the substrates from the outside towards the inside of the passenger compartment or room that it equips. This means that the incident solar light passes through the faces in the increasing order of their number.

The stack is preferably positioned in the glazing so that the incident light coming from outside passes through the first dielectric coating before passing through the first functional metallic layer. The stack is not deposited on the face of the substrate that defines the external wall of the glazing but on the inner face of this substrate. The stack is therefore advantageously positioned on face 2, face 1 of the glazing being the outermost face of the glazing, as is customary.

The material may be intended for applications that require the substrate coated with the stack to have undergone a heat treatment at a high temperature such as a tempering, an annealing or a bending. The glazing of the invention may be in the form of monolithic, laminated or multiple glazing, in particular double glazing or triple glazing.

In the case of a multiple glazing, the stack is preferably deposited on face 2, that is to say that it is on the substrate that defines the external wall of the glazing and more specifically on the inner face of this substrate. A monolithic glazing comprises 2 faces; face 1 is on the outside of the building and therefore constitutes the external wall of the glazing, face 2 is on the inside of the building and therefore constitutes the internal wall of the glazing.

A multiple glazing comprises at least two substrates kept at a distance so as to delimit a cavity filled by an insulating gas (e.g., dry air, Ar, Kr or their mixture). The materials according to the invention are very particularly suitable when they are used in double glazings with enhanced thermal insulation (ETI). A double glazing comprises 4 faces; face 1 is outside of the building and therefore constitutes the external wall of the glazing, face 4 is inside the building and therefore constitutes the internal wall of the glazing, faces 2 and 3 being on the inside of the double glazing.

In the same way, a triple glazing comprises 6 faces; face 1 is outside of the building (external wall of the glazing), face 6 is inside the building (internal wall of the glazing) and faces 2 to 5 are on the inside of the triple glazing. A laminated glazing comprises at least one structure of first substrate/sheet(s)/second substrate type. The stack of thin layers is positioned on at least one of the faces of one of the substrates. The stack may be on the face of the second substrate not in contact with the, preferably polymer, sheet. This embodiment is advantageous when the laminated glazing is assembled as double glazing with a third substrate.

The glazing according to the invention, used in a multiple glazing e.g., a double glazing unit, has internal reflection coloration ranging from neutral, blue and green. Likewise, the glazing has a neutral to blue external reflective coloration. The external color is not too dull at the same time is not too reflective. These two features aid in visual comfort for people facing the interior and exterior of the glazing. Furthermore, these visual appearances change minimally irrespective of the angle of incidence with which the glazing is observed (normal incidence and under an angle). This means that an observer does not have the impression of a significant lack of uniformity in color or in appearance.

The glazing of the invention has colors in transmission in the L*a*b* color measurement system: a*T between -10 and 0, preferably between -8 to -3; in a particular exemplary embodiment a*T is -6.5; b*T between -4 and 5, preferably between -2 to 3; in a particular exemplary embodiment b*T is 2.5.

The glazing of the invention has colors in reflection on the external side in the L*a*b* color measurement system: a*ext between -5 and 0, preferably between -4 to -1; in a particular exemplary embodiment a* ext is -4.3; b* ext between -20 and -1, preferably less than -12 to -2; in a particular exemplary embodiment b* ext is -9.1.

The glazing of the invention has colors in reflection on the internal side in the L*a*b* color measurement system: a*int between -15 and 3, preferably between -10 to 0; in a particular exemplary embodiment a*int is -7.1; b*int between -10 and 0, preferably between -9 to -1; in a particular exemplary embodiment b*int is -3.8.

According to advantageous embodiments, the glazing of the invention in the form of a double glazing comprising the stack positioned on face 2 makes it possible to achieve, in particular, the following performances: a solar factor less than or equal to 35%, preferably less than or equal to 32%, and/or a high selectivity, in order of increasing preference, of at least 1.5, of at least 1.7, and/or a low emissivity, in particular of less than 0.04, and/or sheet resistance no greater than 3 Q/square, and/or a light reflection on the external side of less than or equal to 24%, preferably less than or equal to 20%, and/or a light reflection on the internal side of less than or equal to 20%, preferably less than or equal to 17%, and/or colors ranging from neutral to blue to green in internal reflection, and/or colors ranging from blue to neutral in external reflection. Preferably, the stack is deposited by magnetron sputtering. According to this advantageous embodiment, all the layers of the stack are deposited by magnetron sputtering.

Examples

5 Example 1

Preparation of the Substrates: Stack of thin layers and Heat Treatments

Stack of thin layers, defined below, are deposited on substrates made of clear soda-lime glass with a thickness of 6 mm.

In the example of the invention: 0 the functional layers are layers of silver (Ag), the absorber layer is based on niobium nitride (NbN), the barrier layers are metallic layers made of nickel -chromium alloy (NiCr), the dielectric barrier layers are based on silicon nitride (Si ₃ N ₄ ), the dielectric stabilizing layers are made of zinc oxide (ZnO), 5 the dielectric smoothing layer are based on zinc tin mixed oxide (SnZnOx), the overcoat layers are made of titanium zirconium oxide (TiZrNx) and/or Carbon.

Table 1 lists the materials and thicknesses in nanometers for each layer or coating that forms the stacks as a function of their position with respect to the substrate bearing the stack (final line at the bottom of the table). The “Ref.” 0 numbers correspond to the references from FIG. 3.

Table 1 : Stack of thin layers - Inventive Samples

A Comparative sample was also prepared by constructing the stack of thin layers provided in the prior art Patent US 7166360 by replacing the Ti barrier layers below the silver functional layer with NiCr barrier layers as that taught in the present invention as shown in Table 2.

Table 2: Stack of thin layers - Comparative Sample

Example 2 Solar Control and Optical Properties

Table 3 lists the main optical characteristics measured when the glazings are part of double glazing having a 6/15/6 structure: 6 mm glass/15 mm interlayer space filled with 90% argon and 10% air/6 mm glass, the stack being positioned on face 2 (face 1 of the glazing being the outermost face of the glazing, as is customary). For these double glazings:

TL indicates: the light transmission in the visible region in %, measured according 5 to the illuminant D65 Obs 2; a*T and b*T indicate the a* and b* colors in transmission in the L*a*b* system measured according to the illuminant D65 Obs 2 and measured perpendicularly to the glazing;

Rext indicates: the light reflection in the visible region in %, measured according to 10 the illuminant D65 Obs 2 on the side of the outermost face, face 1; a*Rext and b*R _ext indicate the a* and b* colors in reflection in the L*a*b* system measured according to the illuminant D65 Obs 2 on the side of the outermost face and thus measured perpendicularly to the glazing;

Rint indicates: the light reflection in the visible region in %, measured according to 15 the illuminant D65 Obs 2 on the side of the internal face, face 4; a*Rint and b*Rint indicate the a* and b* colors in reflection in the L*a*b* system measured according to the illuminant D65 Obs 2 on the side of the internal face and thus measured perpendicularly to the glazing.

The colorimetric values at an angle a*g60° and b*g60° are 20 measured on double glazing under an incidence of 60° is shown in Table 4. This takes into account the stability of the colors at an angle.

Table 3: Optical & Solar Control Properties

Table 4: Calorimetric Values

The samples according to the present invention all have internal reflection less than 17%, light transmission between 45% and 60% with samples 1, 3 and 5 having external blue reflective coloration and samples 2 and 4 having external neutral reflective coloration. The examples presented are particularly advantageous since they have, in addition to low solar factor and a high selectivity, low external reflection, particularly less than 20%. The proposed invention therefore makes it possible to achieve combined desired solar performance, optical and aesthetic properties.

The comparative sample was prepared with a much thicker first functional layer such that F1/F2 is not within the desired range of 0.75 and 1.5. It is evident from Table 3 that the internal reflection of such a stack of thin layers is high thereby failing to achieve the combined desired solar performance, optical and aesthetic properties.

Industrial Applicability

The glazing described in the present disclosure finds application as a glazed element in building. In this application case, the glazing may form a double or triple glazing with the coating side of the glass arranged facing the closed space inside the multiple glazing. The glazing may also form a laminated glazing whose stack of layers may be in contact with the thermoplastic adhesive material connecting the substrates, in general PVB. The glazing according to the invention is, however, particularly useful when the multilayer stack is facing the outer environment, whether it is an insulated glazing or laminated glazing, but also optionally a multiple glazing. The glazing may also be enameled. The glazing of the present disclosure can also be annealed, strengthened, toughened, tempered or curved and/or bent.

The tempered glazing can also be used in building wall cladding panel of curtain walling for interior applications. Further an also be used as a side window, rear window or sunroof for an automobile or other vehicle.

Note that not all of the activities described above in the general description or the examples are required, that a portion of a specific activity may not be required, and that one or more further activities may be performed in addition to those described. Still further, the order in which activities are listed is not necessarily the order in which they are performed.

Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims.

The specification and illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The specification and illustrations are not intended to serve as an exhaustive and comprehensive description of all of the elements and features of apparatus and systems that use the structures or methods described herein. Certain features, that are for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in a sub combination. Further, reference to values stated in ranges includes each and every value within that range. Many other embodiments may be apparent to skilled artisans only after reading this specification. Other embodiments may be used and derived from the disclosure, such that a structural substitution, logical substitution, or another change may be made without departing from the scope of the disclosure. Accordingly, the disclosure is to be regarded as illustrative rather than restrictive.

The description in combination with the figures is provided to assist in understanding the teachings disclosed herein, is provided to assist in describing the teachings, and should not be interpreted as a limitation on the scope or applicability of the teachings. However, other teachings can certainly be used in this application.

As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having" or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a method, article, or apparatus that comprises a list of features is not necessarily limited only to those features but may include other features not expressly listed or inherent to such method, article, or apparatus. Further, unless expressly stated to the contrary, "or" refers to an inclusive-or and not to an exclusive-or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

Also, the use of "a" or "an" is employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural, or vice versa, unless it is clear that it is meant otherwise. For example, when a single item is described herein, more than one item may be used in place of a single item. Similarly, where more than one item is described herein, a single item may be substituted for that more than one item.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The materials, methods, and examples are illustrative only and not intended to be limiting. To the extent that certain details regarding specific materials and processing acts are not described, such details may include conventional approaches, which may be found in reference books and other sources within the manufacturing arts.

While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.

List of Elements

TITLE: GLAZING COMPRISING A STACK OF THIN LAYERS HAVING

ABSORBER LAYER FOR LOW INTERNAL REFLECTION AND VARIED

EXTERNAL REFLECTION COLORS

10 Glass Substrate

20 First Dielectric Coating

21, 22 Dielectric Layers

31, 91 Barrier Layers

50 First Functional Layer

40 Second Dielectric Coating

41, 42, 43, 44, 45 Dielectric Layers

32, 92 Barrier Layers

100 Absorber Layer

150 Second Functional Layer

60 Second Dielectric Coating

61, 62 Dielectric Layers

200 Overcoat Layer