CN111201205A

CN111201205A - Article with optical and aesthetic properties

Info

Publication number: CN111201205A
Application number: CN201980003893.6A
Authority: CN
Inventors: T.翁加雷洛; A.迪盖
Original assignee: Saint Gobain Glass France SAS
Current assignee: Saint Gobain Glass France SAS
Priority date: 2018-09-20
Filing date: 2019-09-11
Publication date: 2020-05-26
Also published as: FR3086285A1; WO2020058061A1

Abstract

The invention relates to an article having neutral optical properties, which has a colour-neutralising function when it comprises a stack comprising metallic functional layers. The article comprises a transparent substrate comprising, on and in contact with at least one of its surfaces, a first layer based on zinc-tin nitride and/or based on nickel-chromium nitride.

Description

Article with optical and aesthetic properties

The invention relates to an article having neutral optical properties, which has a colour-neutralising function when it comprises a stack of metal-containing functional layers. The invention also relates to a method for obtaining such an article.

The proportion of glass areas in buildings and vehicles is increasing to meet the demands of users for natural lighting.

For reasons of energy saving and comfort, these glass areas can be functionalized so as to act on the incident solar and/or infrared radiation and reduce the "greenhouse" effect. These areas are usually functionalized by depositing on their surface a layer stack comprising a metallic functional layer. These layers impart a so-called "select" function to these surfaces, and to the glazing (glazing) containing these surfaces, which reduces the amount of energy transmitted through the glazing to the interior.

In addition to these heat selection functions, there may be aesthetic requirements in terms of color. In certain applications, in particular in the building sector, the glass region must have a surface which appears to be neutral in color (i.e. preferably close to gray in the blue-green color range) in transmission and in reflection externally and/or internally.

However, the use of functional laminates capable of imparting a thermally selective function to the glass surface is often incompatible or even contrary to the aesthetic requirements in terms of colour. In particular, the optical properties of the stack of these functional layers make it impossible to easily obtain neutral colors.

For example, in the case of the most widespread stacks comprising functional layers of silver-based metals, complex adjustments have to be made, on the one hand to the thickness of the functional layers and, on the other hand, to the properties and optical thickness of the layers constituting the dielectric assembly separating them. These adjustments determine the optical interaction between the different layers. The next problem is to find a compromise between thermal and aesthetic properties.

This problem becomes even more complicated when it is desired to maintain high light transmittance or insignificant mirror effect. In particular in this case, the silver-based metal functional layer cannot be thickened as a means of providing an article in which it contains a neutral color.

One possible alternative is to color the bulk of the substrate that makes up the glass region by incorporating colorant additives into its composition. For example, in the case of substrates made of mineral glass, it is possible to use colorant oxides, which are mixed into the vitrifiable mixture from which they are made.

One of the main drawbacks of this method is that special processes have to be developed or existing processes have to be modified in order to produce such coloured substrates specifically. For example, when producing colored mineral glass substrates on lines based on the float process, these lines can only produce one color at a time. It is then necessary to produce a certain amount of glass for each colour, which is then stored for months or even years before sale. In the event that the inventory is not sold or if the manufactured inventory is sold out sooner than expected, there can be a tangible and economic loss.

Due to the costs incurred by this approach, only a small number of manufacturers are able to implement. As a result, consumers or glazingers may rely on a few suppliers, or even a single supplier, and on a limited number of mineral glass substrate compositions, which may not be suitable for new needs. This economic and material dependent situation can quickly become detrimental to the development of new products.

The present invention addresses these problems. One subject thereof is an article comprising a transparent substrate comprising, on and in contact with at least one of its surfaces, a first absorbing layer based on zinc-tin nitride and/or nickel-chromium nitride.

The articles of the present invention have a neutral color, i.e., a gray color in the blue-green color range. In particular, the values of the two parameters a and b in the system L a b are close to zero, in particular in transmission and external reflection.

The article of the invention also has a colour-neutralizing function when it is used as a support for a stack of thin layers containing a metallic functional layer, in particular a thin metallic layer based on silver. In other words, when the article acts as a support for a stack containing thin metal functional layers, it is able to neutralize the color of the stack and maintain a neutral color overall. It also allows the physical thickness of the thin metal functional layer and/or other thin metal layers contained in the stack to be reduced without compromising the optical and thermal properties of the stack.

Another advantage of the article of the invention is that the manufacture of the object is simpler than those obtained using methods based on the bulk colouring of the substrate or, where appropriate, on the adjustment of the physico-chemical characteristics of the thin layers forming the stack, which may act as a carrier. An example of a method by which the article of the invention can be obtained is described below.

The substrate comprised in the article of the invention is transparent. It is preferred not to color it in its entirety, although this may be the case without compromising its transparency. In this respect, another advantage of the present invention is that it can be applied to various types of transparent substrates.

Various embodiments of the invention are described below, the features of which are shown in the accompanying drawings.

Figure 1 is a schematic view of a first embodiment of the article of the invention.

Figure 2 is a schematic view of a second embodiment of the article of the invention.

Figure 3 is a schematic view of a third embodiment of the article of the invention.

FIG. 4 is a schematic cross-section of a double glazing comprising an article of the invention.

FIG. 5 is a schematic representation of a cross-section of a single glazing comprising an article of the invention.

In the remainder of this document, reference is made to the accompanying drawings, in which the numbers refer to elements described below.

In this specification, the following definitions and conventions are used.

The substrate may be positioned horizontally, vertically, or inclined, depending on the choice of embodiment of the invention. The layer number order of the assembly of layers is defined starting from the substrate in the direction of the stacking surface opposite the substrate. For example, a metal functional layer F1 and a dielectric layer assembly E1 are proximate to the substrate. The metal functional layer F3 and the dielectric layer assembly E4 were furthest from the substrate.

The terms "above" and "below," which define the position of a layer or layer assembly and are defined relative to the position of a functional layer, respectively, refer to the layer or the layer assembly being closer to or further from the substrate. The two terms "above" and "below" in no way imply that the layer or layer assembly they define is in contact with the functional layer with respect to which they are defined. They do not exclude the presence of other intermediate layers between the two layers. The expressions "contact is made" and "contact" are explicitly used to indicate that there are no further layers between them.

The terms "exterior" and "interior" when defining a substrate surface or an optical or physical parameter of a substrate surface refer to the exterior and interior orientation of the substrate surface toward an asset (which may be, for example, a building or vehicle in which the substrate is used), respectively.

Unless otherwise specified or stated, the term "thickness" when used with respect to a layer corresponds to the actual or collective physical thickness e of the layer. Expressed in nanometers. The expression "optical thickness" is used to indicate with certainty the optical thickness of the layer, indicated as e 0. It is defined by the relation e0 = n × e, where n is the refractive index of the layer and e is its true or geometric physical thickness. The refractive index of the layer was measured at an electromagnetic wavelength of 550 nm. The optical thickness is also expressed in nanometers.

The expression "dielectric layer assembly" refers to one or more layers in contact with each other, constituting a stack that is dielectric as a whole, i.e. it does not have the function of a metallic functional layer. If the dielectric assembly comprises multiple layers, the latter may itself be dielectric. The actual or geometric physical thickness and the optical thickness of the dielectric layer assembly correspond to the sum of the actual or geometric physical thicknesses and the sum of the optical thicknesses of each of its constituent layers, respectively.

In the present description, the expression "based on" for defining the content of a material or layer means that the fraction per unit weight of the ingredients it contains is at least 50%, in particular at least 70% and preferably at least 90%.

Hexanoic acid transmittance, light reflection and solar factor were defined, measured according to standards EN 410, EN 613, ISO 9050 and ISO 10292. The color was measured according to standard ISO 11664 in the L a b CIE 1976 color space with a light source D65 and a reference observer field of view of 2 °.

The real word "stoichiometric ratio" and adjectives derived therefrom must be interpreted in the conventional sense in the technical field. This means in particular that the proportions of the chemical elements forming the compound correspond to the proportions of the "determined compound", as determined by thermochemical mapping or by the usual practice in the technical field.

A first embodiment of the article of the invention is schematically shown in figure 1. The article 1000 comprises a transparent substrate 1001 and a first layer 1002 based on zinc-tin nitride and/or based on nickel-chromium nitride. The first layer 1002 is on and in contact with at least one surface 1001a of a transparent substrate 1001.

The physical thickness of the first layer 1002 based on zinc-tin nitride and/or based on nickel-chromium nitride may be 2 to 20 nm. In a preferred embodiment, the physical thickness is at least 2 nm. The zinc-tin nitride and/or nickel-chromium nitride of the first layer may or may not be stoichiometric.

The first layer 1002 can be a zinc-tin nitride based layer. As a non-limiting example, the atomic ratio of zinc to tin, Zn: Sn, may be from 1 to 9. The atomic ratio N (Zn + Sn) of nitrogen N to the sum of zinc and tin may be 0.1 to 1.5. In particular, the atomic ratio Zn: Sn may advantageously be between 1.4 and 8, and the atomic ratio N (Zn + Sn) may be between 0.5 and 1.

The real part of the refractive index at 550 nm of the first layer based on zinc-tin nitride is advantageously between 2.4 and 4. The optical thickness of the first layer based on zinc-tin nitride may be 4.5 nm to 80 nm.

The first layer 1002 may be a nickel-chromium nitride based layer. As a non-limiting example, the atomic ratio of zinc to tin, Ni: Cr, may be from 1 to 4. The atomic ratio N (Ni + Cr) of nitrogen N to the sum of Ni and Cr may be 0.3 to 1. In particular, the atomic ratio Ni: Cr may advantageously be from 2 to 4, and the atomic ratio N (Ni + Cr) may be from 0.5 to 1.

In a variant of the first embodiment of the invention, the article 1000 consists of a transparent substrate 1001 and a first layer 1002 based on zinc-tin nitride and/or on nickel-chromium nitride. The first layer 1002 is on and in contact with at least one surface 1001a of a transparent substrate 1001.

In other embodiments of the article of the present invention, the transparent substrate further comprises a thin-layer stack on and in contact with said first layer, the thin-layer stack comprising at least one metallic functional layer.

In a second embodiment of the article of the invention, the thin-film stack comprises two metallic functional layers separated by a dielectric thin-film assembly. This embodiment is schematically shown in figure 2. The article 2000 comprises a transparent substrate 1001 and a first layer 1002 based on zinc-tin nitride and/or on nickel-chromium nitride, said first layer 1002 being on and in contact with at least one surface 1001a of the transparent substrate 1001. A stack 2001 of thin layers comprising two metallic

functional layers

2004, 2008 is placed on and in contact with a surface 1002a of said first layer 1002. The two metal

functional layers

2004, 2008 are separated by a dielectric thin layer assembly 2006.

In the embodiment shown in fig. 2, the stack of thin layers 2001 further comprises a dielectric assembly 2002 between the first layer 1002 and the first metal functional layer 2004, and a dielectric layer assembly 2010 between the second metal functional layer 2008 and the surface 2001a of the stack.

The stack 2001 may further comprise so-called

barrier layers

2005, 2009 placed over and in contact with the metallic

functional layers

2004, 2008. The role of this layer (usually of very small thickness) is to protect the metal layer when subsequent layers are deposited in an oxidizing atmosphere, or when certain elements (such as oxygen) tend to migrate from one layer to another during heat treatment. If it is desired to protect the respective metallic

functional layers

2004, 2008, it is advantageous to place the barrier layers 2005, 2009 over and in contact with the respective metallic

functional layers

2004, 2008 contained in the stack 2001. This layer is preferably based on a metal or alloy selected from Ti and NiCr. Its thickness is generally equal to or less than 5 nm.

It is also possible to place the barrier layers 2003, 2007 under and in contact with the metal

functional layers

2004, 2008. If it is desired to protect each of the metallic

functional layers

2004, 2008, it is advantageous to place

barrier layers

2003, 2007 under and in contact with each of the metallic

functional layers

2004, 2008 contained in the stack 2001.

In certain applications, the integrated-view stack 2001 may be advantageous to include a protective layer 2011 to protect it from potential physico-chemical degradation caused by the atmosphere or external environment with which it may come into contact. In this regard, the stack of layers 2001 may further comprise a protective layer 2011 placed on its surface that may be in contact with the atmosphere. The physical thickness of the protective layer is typically equal to or less than 5 nm. As a non-limiting example, the protective layer may be a layer based on the alloy TiZr.

In a third embodiment of the invention, the thin-film stack comprises three functional layers, which are separated from one another by a dielectric thin-film assembly. This embodiment is schematically shown in figure 3. This article 3000 comprises a transparent substrate 1001 and a first layer 1002 based on zinc-tin nitride and/or on nickel-chromium nitride, said first layer 1002 being on and in contact with at least one surface 1001a of the transparent substrate 1001. A stack 3001 of thin layers comprising three metallic

functional layers

3004, 3008, 3012 is placed on and in contact with surface 1002a of said first layer 1002. The three metal

functional layers

3004, 3008, 3012 are separated from each other by

dielectric layer assemblies

3006, 3010.

In this third embodiment, the stack of thin layers 3001 further comprises a dielectric assembly 3002 between the first layer 1002 and the first metal functional layer 3004, and a dielectric assembly 3014 between the second metal functional layer 3012 and the stack surface 3001 a.

The stack 3001 may further comprise so-called

barrier layers

3005, 3009, 3013 placed above and in contact with the metallic

functional layers

3004, 3008, 3012. If protection of the respective metallic

functional layers

3004, 3008 is required, it is advantageous to place

barrier layers

3005, 3009, 3013 above and in contact with the respective metallic

functional layers

3004, 3008, 3012 comprised by the stack 3001. This layer is preferably based on a metal or alloy selected from Ti and NiCr. Its thickness is generally equal to or less than 5 nm.

It is also possible to place the barrier layers 3003, 3007, 3011 under and in contact with the metal

functional layers

3004, 3008, 3012. If protection of the respective metallic

functional layers

3004, 3008, 3012 is required, it is advantageous to place

barrier layers

3003, 3007, 3011 under and in contact with the respective metallic

functional layers

3004, 3008, 3012 comprised by the stack 3001.

In certain applications, it may be advantageous to include a protective layer 3015 to protect it from potential physico-chemical degradation caused by the atmosphere or external environment with which it may come into contact. In this regard, the stack of layers 3001 may further comprise a protective layer 3015 disposed on a surface thereof that may be in contact with the atmosphere. The physical thickness of the protective layer is typically equal to or less than 5 nm. As a non-limiting example, the protective layer may be a layer based on the alloy TiZr.

The stoichiometric ratios are not necessarily perfectly met for the compounds contained in the layers of the dielectric assembly, in the barrier layer or in the protective layer, in particular those shown as examples. In particular, they may deviate from the stoichiometric ratio due to their content of oxygen, nitrogen and/or other elements, such as dopant elements.

Preferably, the metal functional layers of the thin-film stack are based on silver. Their physical thickness may advantageously be from 7 to 20 nm.

When the article of the invention comprises a stack of thin layers comprising at least one metallic functional layer, the physical thickness of this first layer may advantageously be between 0.5 and 10 nm, preferably between 0.5 and 8 nm.

The transparent substrate of the present invention may be a mineral or organic, rigid or flexible, planar or curved substrate. It is preferably colorless, non-opaque and non-translucent to minimize light absorption and thereby maintain maximum light transmission.

Examples of organic substrates that may be advantageously used in the practice of the present invention are polymeric materials such as polyethylene, polyesters, polyacrylates, polycarbonates, polyurethanes, polyamides. These polymers may be fluoropolymers.

Examples of mineral substrates that can be advantageously used in the present invention are mineral glass or glass-ceramic plates. The glass is preferably a soda-lime-silica glass, a borosilicate glass, an aluminosilicate glass or even a boroaluminosilicate glass.

In a preferred embodiment of the invention, the transparent substrate is a soda-lime-silica mineral glass plate.

The articles of the present invention may be used for single, laminated or multiple layer glazing. In this regard, the present invention also relates to a glazing comprising an article according to any of the above embodiments.

A single glazing comprises a single glass sheet, which is a problem with single layer glazings. When the article of the invention is used as a monolithic glazing, the first layer and optionally the stack of thin layers are preferably deposited on the face of the glass pane facing the interior of the room of the building on which the glazing is mounted. In such a configuration, it is advantageous to protect the first layer and optionally the stack of thin layers from physical or chemical degradation using suitable means.

A multiple layer glazing comprises at least two parallel glass sheets separated by a cavity filled with an insulating gas. Most multiple layer glazing is double or triple layer glazing, i.e. they comprise two or three glazing panes respectively. When the article of the invention is used as a component of a multi-layer glazing, the first layer and optionally the stack of thin layers are preferably deposited on the face of the glass sheet facing inwards, in contact with an insulating gas. An advantage of this arrangement is that the stack is protected from chemical or physical degradation by the external environment.

A laminated glazing comprises at least two parallel glass sheets separated by an interlayer sheet. The interlayer sheet is typically an organic material such as polyvinyl butyral (PVB). When the article of the invention is used as a component of a laminated glazing, the first layer and optionally the stack of thin layers may be deposited on either side of the glass sheet, whether or not those sides contact the interlayer sheet. It may be advantageous to deposit on the face of the glass sheet in contact with the interlayer sheet to prevent chemical or physical deterioration by the external environment. However, it must be noted that the composition of the sandwich panel does not have properties that interact with and cause deterioration of the stacked layers.

Figure 4 schematically shows a cross-section of an example of a double glazing 4000 comprising an article of the invention. In this figure, (E) corresponds to the exterior of the asset to which the glazing is mounted and (I) corresponds to the interior of the asset. The glazing 4000 comprises a first glass plate 4001 having an inner surface 4001a and an outer surface 4001b, a second glass plate 4002 having an inner surface 4002a and an outer surface 4002b, a cavity 4004 filled with an insulating gas, a spacer 4005, and a sealant 4006. The glass plate 4001 comprises a first layer based on zinc-tin nitride and/or nickel-chromium nitride on and in contact with the inner surface 4001a thereof that contacts the gas of the gas-insulated cavity 4004. The glass plate 4001 may further comprise a stack of thin layers comprising at least one functional layer of a metal on and in contact with the first layer. This assembly consists of the first layer and the stack of thin layers is represented in fig. 4 by element 4003. The assembly 4003 is placed so that its outer surface 4003a (opposite the surface 4001a of the glass plate 4001) faces the interior (I) of the asset (e.g., a building or an automobile) in which the glazing is used.

FIG. 5 schematically shows a cross-section of an example of a single ply glazing 5000 comprising an article of the invention. In this figure, (E) corresponds to the exterior of the asset to which the glazing is mounted and (I) corresponds to the interior of the asset. The glazing 5000 comprises a single glass plate 5001 having an inner surface 5001a and an outer surface 5001 b. The glass plate 5001 includes a first layer based on zinc-tin nitride and/or nickel-chromium nitride on and in contact with its inner surface 5001 a. The glass sheet 5001 can further comprise a stack of thin layers on and in contact with the first layer comprising at least one functional layer of a metal. This assembly consists of the first layer, and the stack of thin layers is represented in fig. 5 by element 5003. The assembly 5003 is positioned so that its outer surface 5003a (opposite surface 5001a of glass sheet 5001) faces the interior (I) of the asset (e.g., building or automobile) in which the glazing is used.

Another subject of the invention is the manufacture of an article with neutral optical properties, which has a colour-neutralising function when it comprises a stack containing metallic functional layers.

The method comprises the following steps:

(a) providing a transparent substrate;

(b) a first layer based on zinc-tin nitride and/or based on nickel-chromium nitride is deposited on and in contact with at least one surface of the transparent substrate.

The first layer based on zinc-tin nitride and/or based on nickel-chromium nitride is deposited on the transparent substrate using conventional deposition methods known to the person skilled in the art.

In a preferred embodiment of the method of the invention, the first layer based on zinc-tin nitride and/or based on nickel-chromium nitride is deposited using a magnetron cathode sputtering apparatus. One advantage of this embodiment is that the method is easy to implement and is suitable for many types of substrates.

As a non-limiting example, when depositing the first layer based on zinc-tin nitride using a magnetron cathode sputtering apparatus, the following conditions may be used: a pressure of 2 μ bar, a frequency of 100 kHz, a power of 250W, an argon flow of 15 sccm (standard cubic centimeters per minute), a molecular nitrogen flow of 50 to 100 sccm, and a metal target based on tin and zinc, the weight ratio of tin to zinc being 50:50 to 15: 85.

As a non-limiting example, when depositing the first layer based on nickel-chromium nitride using a magnetron cathode sputtering apparatus, the following conditions may be used: a pressure of 2 μ bar, a frequency of 100 kHz, a power of 250W, an argon flow of 15 to 50 sccm (standard cubic centimeters per minute), a molecular nitrogen flow of 15 to 40 sccm, and a nickel and chromium based metal target, the weight ratio of nickel to chromium being 50:50 to 80: 20.

Another advantage of the manufacturing method of the invention is that it can be easily implemented in existing equipment for physically depositing thin-layer stacks. For example, it may be implemented using a complementary deposition module placed upstream of the apparatus, or instead of a module of the apparatus, which is located upstream of the apparatus.

In this regard, in one embodiment of the method of the present invention, the method may further comprise depositing a thin-layer stack comprising at least one silver-based functional layer on and in contact with said first layer after step (a).

The effects and advantages of the present invention are illustrated by the following examples.

A number of examples and a number of comparative examples of articles of the present invention have been manufactured. Values of various parameters capable of evaluating the optical properties and thermal properties of each of examples and comparative examples were measured. These values were measured on either a single glazing as shown in figure 5 or a double glazing as shown in figure 4.

This example and the comparative example comprise a first layer 1001 and a

possible stack

2001, 3001, said first layer 1001 and said

stack

2001, 3001 being deposited on one surface of a transparent substrate. The conditions for depositing this layer are those conventionally used by the person skilled in the art for magnetron cathode sputtering (magnetron process) and are widely described in the literature (for example in patent applications WO2012/093238 and WO 2017/00602. when the first layer is a layer based on nickel-chromium nitride, the target used for depositing the first layer 1001 of this embodiment is a metal target based on nickel and chromium, with a weight ratio of nickel to chromium of 80:20, and when the first layer is based on zinc-tin nitride, the target is a metal target based on tin and zinc, with a weight ratio of tin to zinc of 15: 85.

In the case of single or double glazing, the parameters used to evaluate the optical and thermal properties of the examples and comparative examples are as follows:

-light transmittance in the TL visible spectrum;

-g, sun factor;

rint, the value of reflection of light in the visible spectrum, expressed in percentages, measured with a light source D65 and a field of view of 2 ° to the observer on the

inner surface

4002a, 5003a of the glazing;

-at and at, the values of the parameters a and b measured in transmission in the L at and b CIE 1976 color space, the light source being D65, the field of view of the observer being 2 °, and the viewing angle with respect to the normal to the glazing surface being zero;

-Rext, the value of light reflection in the visible spectrum, expressed in percentage, measured with a light source D65 and a field of view at 2 ° to the observer on the

outer surface

4001b, 5001 b;

-a Rext and b Rext, the values of the parameters a and b, respectively, measured in reflection in L a b CIE 1976 color space, the light source being D65 and the field of view to the observer being 2 ° on the

outer surface

4001b, 5001b of the glazing;

-a and b Rint, respectively, the values of the parameters a and b measured in reflection in L a b CIE 1976 colour space, the light source being D65, the field of view to the observer being 2 ° on the

inner surface

4002a, 5003a of the glazing.

The light transmittance TL, solar factor g and selectivity s in the visible spectrum of hexanoic acid, as well as the internal reflection Rint and the external reflection Rext in the visible spectrum, are defined, measured and measured according to the standards EN 410, EN 613, ISO 9050 and ISO 10292. The color was measured according to standard ISO 11664 in the L a b CIE 1976 color space with a light source D65 and a reference observer field of view of 2 °.

Two examples Ex1 and Ex2 of a first embodiment of an article according to the invention were made, the first embodiment being shown in fig. 1. They are described in table 1. In both examples, the transparent substrate 1001 was a first soda-lime-silica mineral Glass (Glass 1) of the type sold under the trade name PLANICLEAR by Saint-Gobain Glass. In example Ex1, the first layer 1002 is a nickel-chromium nitride based layer. In example Ex2, the first layer 1002 is a zinc-tin nitride based layer. In both examples Ex1 and Ex2, the thickness of the first layer 1002 was 5 nm. The glass 1 has a thickness of 6 mm. The physical thicknesses (in nanometers) of the respective layers are shown in table 1.

For comparison, table 1 includes a comparative example CEx1, where the substrate of the article does not include the first layer 1002. The transparent substrate was replaced by a second soda lime silica mineral Glass (Glass 2) having a neutral color, which was bulk tinted and of the type sold under the trade name SGG Parsol @bySaint-Gobain Glass. The glass 2 has a thickness of 6 mm.

The values of the parameters used to evaluate the optical and thermal properties of the examples and comparative examples of table 1 are collated in table 2.

[ Table 1]

[ Table 2]

TABLE 2	TL	a*T	b*T	Rext	a*Rext	b*Rext
							Example 1	75.9	0.48	4.13	21.86	1.66	-3.8
Example 2	48.5	0.5	0.77	18.68	0	0.6
							Comparative example 1	43	0.4	-1.4	5	0.1	0.7

The values of parameters TL, a × T, b × T, a × Rext and b × Rext for example Ex2 and comparative example CEx1 are similar. The light transmission of the article of example 2 was slightly higher than that of the article of comparative example CEx 1. This shows that the article of the invention, when it comprises a first layer based on chromium-nickel nitride, is able to obtain the same optical properties in terms of light transmittance and colour as a neutral coloured glass.

Example Ex1 shows that, when the article according to the invention comprises a first layer based on zinc-tin nitride, the values of the parameters a T, b × T, a × Rext and b Rext are close to those of the same parameters of the article of comparative example CEx 1. The article of example Ex1 had a less neutral color compared to the article of example Ex 2. However, its light transmittance was higher and its first layer had a thickness at least two times less than that of the article of example 2. The article of example Ex1 can be a beneficial compromise when high light transmission, reduced layer thickness, near neutrality in reflection, and neutral color in transmission are sought simultaneously.

Four examples Ex3, Ex4, Ex5 and Ex6 of a second embodiment of an article according to the present invention were made, the second embodiment being shown in fig. 2. They are described in table 3. In these examples, the transparent substrate was a first soda-lime-silica mineral Glass (Glass 1) of the type sold under the trade name PLANICLEAR @bysaint-Gobain Glass. The glass 1 has a thickness of 6 mm.

In examples Ex3 and Ex4, the first layer 1002 was a zinc-tin nitride based layer. In examples Ex5 and Ex6, the first layer 1002 was a nickel-chromium nitride based layer.

For comparison, table 3 includes a comparative example CEx2, where the substrate of the article did not include the first layer 1002. The transparent substrate was the same as examples Ex3, Ex4, Ex5 and Ex 6.

In examples Ex3, Ex4, Ex6 and comparative example CEx2, the transparent substrate further comprises a thin-layer stack comprising two functional layers of a silver-based metal on and in contact with said first layer 1002. The physical thicknesses (in nanometers) of the respective layers are shown in table 3.

The values of the parameters used to evaluate the optical and thermal properties of the examples and comparative examples of table 3 are collated in table 4. These values were measured on double glazing comprising articles of example Ex3, Ex4, Ex5, Ex6 and comparative example CEx 2. The double glazing 4000 has the following 6/16/4 structure: soda-lime-silica glass plate 4001 with a thickness of 6 mm/cavity 4004 with a thickness of 16 mm filled with an insulating gas comprising at least 90% argon/soda-lime-silica glass plate 4002 with a thickness of 4 mm. In this figure, the first layer 1002 and the stack of thin layers 3001 are represented by element 4003. They are deposited on the inner surface 4001a on a glass plate 4001 having a thickness of 6 mm.

[ Table 3]

[ Table 4]

TABLE 4	g	TL	a*T	b*T	Rext	a*Rext	b*Rext	Rint	a*Rint	b*Rint
											Example 3	31	51.5	-3.82	0.62	13.81	-1.87	-1.56	21	0.9	0.7
Example 4	25	37.3	-2.95	-1.17	12	-1.4	-6	14	0.4	0
											Example 5	31	52	-4	0	13.8	-1	-3	21	0.7	0.44
Example 6	25	37.4	-5	0	11.2	-0.8	-5.8	17	-0.7	-1
											Comparative example 3	28	52	-10.5	-1.5	18	-3	-9	22.5	9.5	4

The values of the parameters a T, b T, a Rext, b Rext, a Rint and b Rint of examples Ex3, Ex4, Ex5 and Ex6 are closer to zero than those of comparative example CEx 2. This shows a colour neutralisation function when the article of the invention comprises a stack comprising metallic functional layers. It is thus possible to impart a neutral color to the stack containing the metal functional layers.

The physical thickness of the silver-based metal functional layers of examples Ex3 and Ex5 was less than the physical thickness of the same layers of comparative example CEx 2. The values of light transmittance and internal and external reflection for both examples and the comparative example are similar. The article of the invention is therefore also capable of reducing the physical thickness of the functional layer based on silver, with respect to an article comprising a stack of thin layers which itself comprises a metallic functional layer, but which does not comprise any first layer based on zinc-tin nitride and/or nickel-chromium nitride, and which maintains the same properties in terms of light transmission and reflection.

Example Ex7 of a third embodiment of an article according to the invention was made, the third embodiment being shown in figure 3. Which is described in table 5. In this example, the transparent substrate was a first soda-lime-silica mineral Glass (Glass 1) of the type sold under the trade name PLANICLEAR @bysaint-Gobain Glass. The glass 1 has a thickness of 6 mm. The first layer 1002 is a zinc-tin nitride based layer. The transparent substrate comprises, on and in contact with said first layer, a thin-layer stack 3001 comprising three functional layers of a silver-based metal. The physical thicknesses of the individual layers of the stack are shown in table 5. They are expressed in nanometers.

For comparison, table 5 includes a comparative example CEx3, where the substrate of the article did not include the first layer 1002. The transparent substrate was the same as in example Ex 7.

The values of the parameters used to evaluate the optical and thermal properties of example Ex7 and the comparative example of table 5 are collated in table 6. These values were measured on double glazing comprising articles of example Ex7 and comparative example CEx 3. The double glazing 4000 has the following 6/16/4 structure: soda-lime-silica glass plate 4001 with a thickness of 6 mm/cavity 4004 with a thickness of 16 mm filled with an insulating gas comprising at least 90% argon/soda-lime-silica glass plate 4002 with a thickness of 4 mm. In this figure, the first layer 1002 and the stack of thin layers 3001 are represented by element 4003. They are deposited on the inner surface 4001a on a glass plate 4001 having a thickness of 6 mm.

[ Table 5]

[ Table 6]

	TL	g	a*T	b*T	a*Rext	b*Rext	a*Rint	b*Rint
									Comparative example 3	46	22	-5.4	-1.15	-5	-10	-11.4	-7.3
Example 7	46	22	-3.18	-2.43	-3	-3	-4	-4

The values of the parameters a T, b T, a Rext, b Rext, a Rint and b Rint of example Ex7 are closer to zero than those of comparative example CEx 3. This again indicates that the article of the invention has a colour neutralising function when it comprises a stack comprising metallic functional layers.

Claims

1. An article comprising a transparent substrate comprising, on and in contact with at least one surface of said transparent substrate, a first layer based on zinc-tin nitride and/or based on nickel-chromium nitride.

2. An article as claimed in claim 1, such that the transparent substrate further comprises, on and in contact with the first layer, a stack of thin layers comprising at least one metallic functional layer.

3. An article as claimed in claim 2, such that the stack of thin layers comprises two metallic functional layers separated by a dielectric thin-layer assembly.

4. An article as claimed in claim 2, such that the stack of thin layers comprises three functional layers, each separated from each other by a dielectric thin-layer assembly.

5. An article as claimed in any one of claims 2 to 4, such that the one or more metallic functional layers are silver-based.

6. An article as claimed in claim 5, such that the physical thickness of the one or more functional layers of silver-based metal is from 7 to 20 nm.

7. An article as claimed in any one of claims 2 to 6, such that the physical thickness of the first layer is from 0.5 to 8 nm.

8. An article as claimed in any one of claims 1 to 6, such that the physical thickness of the first layer is at least 2 nm.

9. An article as claimed in any one of claims 1 to 8, such that the first layer is a zinc-tin nitride based layer.

10. An article as claimed in any one of claims 1 to 8, such that the first layer is a chromium-nickel nitride based layer.

11. An article as claimed in any one of claims 1 to 10, such that the transparent substrate is a soda-lime-silica mineral glass plate.

12. A method of manufacturing an article having neutral optical properties with color neutralization functionality, the method comprising the steps of:

(a) providing a transparent substrate;

13. The manufacturing method as claimed in claim 12, such that the method further comprises, after step (a), depositing a stack of thin layers comprising at least one silver-based functional layer on and in contact with the first layer.

14. A method of manufacturing an article as claimed in claim 12 or 13, such that the first layer based on zinc-tin nitride and/or based on nickel-chromium nitride is deposited using a magnetron-type cathode sputtering apparatus.

15. Glazing comprising an article as claimed in any of claims 1 to 11.