Material comprising a two-layer functional coating having two layers based on silver and an element made of absorbent layers

Abstract

The invention relates to a material comprising a transparent substrate coated with a functional coating, which successively alternates, starting from the substrate, between two continuous silver-based functional metal layers and three dielectric coatings. The first dielectric coating comprises a layered element comprising: - a first layer comprising silicon, selected from a layer of nitride, of oxide or of oxynitride; - a discontinuous silver-based layer comprising silver nanoparticles, deposited directly on the first silicon-based layer; - a second layer comprising silicon, selected from a layer of nitride, of oxide or of oxynitride, deposited directly on the discontinuous silver-based layer.

Description

[0001] Description

[0002] Title of the invention: Material comprising a two-layer silver-based functional coating and an absorbing layered element

[0003] The invention relates to a material comprising a transparent substrate coated with a functional coating capable of acting on solar radiation and / or infrared (IR) radiation with two silver-based functional layers, the functional coating further comprising a layered element having particular absorption properties. The invention also relates to glazings comprising these materials as well as the use of such materials for manufacturing thermal insulation and / or solar protection glazings.

[0004] In the remainder of the description, the term “functional” qualifying “functional coating” or “functional layer” means “capable of acting on solar radiation and / or infrared radiation”.

[0005] The glazing can be used for both buildings and vehicles, in particular to prevent excessive overheating, so-called "solar control" glazing, and / or to reduce air conditioning requirements.

[0006] The selectivity "S" makes it possible to evaluate the performance of these glazings. It corresponds to the ratio of light transmission in the visible TL VjS of the glazing on the solar factor FS of the glazing (S = TL VjS / FS). The solar factor "FS or g" corresponds to the ratio in % between the total energy entering the room through the glazing and the incident solar energy. High selectivity corresponds to obtaining a high transmission of visible light coupled with selective filtering of UV and IR.

[0007] Achieving high selectivity should not be at the expense of aesthetics, particularly color. Generally, the goal is to achieve the most neutral aesthetic possible in terms of transmission, external and internal reflection. This color neutrality must also be achieved regardless of the viewing angle relative to the glazing.

[0008] Known selective glazings comprise transparent substrates coated with a functional coating. Functional coatings comprising silver-based functional layers generally perform better in terms of selectivity compared to other known infrared-reflecting functional coatings such as coatings comprising conductive oxide-based layers, layers based on other metal layers or IR-absorbing layers.

[0009] When seeking to increase selectivity, the aim is to selectively reduce transmission in the infrared region (above 750 nm). One solution is to increase the number of silver-based functional layers. When determining transmission curves as a function of wavelength, the following observations are made. The higher the number of silver-based functional layers, the more the transmission profile is sharpened over the visible wavelength range and the narrower the base of the peak corresponding to absorption. However, the cutoff is not sharp and often extends into the visible red wavelength range. Absorption therefore becomes significant at the extreme values ​​of the visible spectrum corresponding to red absorption around 700 nm.

[0010] Absorbing in this visible region does not result in a significant reduction in light transmission. This phenomenon is explained by the fact that the determination of light transmission takes into account the sensitivity of the human eye or visual acuity. The sensitivity of the eye, depending on the wavelength, gradually decreases on either side of a maximum between 495 and 555 nanometers (nm). The human eye is therefore less sensitive to the extreme wavelengths of the visible range, particularly to wavelengths in the range of 630 to 780 nm. Light transmission is slightly impacted by absorption between 630 and 780 nm because we are absorbing in an area where the human eye is less sensitive. On the other hand, absorbing in this area significantly reduces the total energy entering the room or vehicle and therefore lowers the solar factor without significantly reducing light transmission.

[0011] Ultimately, the small decrease in light transmission coupled with the large reduction in energy transmission leads to a clear improvement in selectivity.

[0012] For example, the selectivities achieved in double glazing using functional coatings comprising 1, 2, 3 or 4 silver-based layers are respectively approximately 1.2, 1.7, 2.0 and 2.25.

[0013] However, absorption in the visible red wavelength range between 630 and 780 nm has a strong impact from a color perspective. When light rays reach the eyes, they are captured by photoreceptors in the retina. There are three types of photoreceptors, each with a spectral sensitivity to a region of the color spectrum: cones more sensitive to blue light (peak centered at approximately 420 nm), others to green light (peak centered at 530 nm), and the third type of cone to red light (peak centered at 565 nm). Absorbing light between 630 and 780 nm, i.e. in the area corresponding to the predominant absorption region of red light, results in a perception of complementary colors, particularly green. In conclusion, reducing the transmission in the red gives a green tint to the glazing in transmission.

[0014] To limit this green coloration, several avenues are possible. The traditional approach to achieving both high selectivity and color neutrality involves developing increasingly complex functional coatings. Functional coatings comprise several silver-based metallic functional layers, each arranged between two dielectric coatings comprising several dielectric layers. Such glazing improves solar protection while maintaining high light transmission. Colors are optimized by exploiting optical interference phenomena. However, for high levels of selectivity, this solution is not sufficient. A compromise between neutrality and selectivity must then be found.

[0015] Indeed, two-layer functional coatings based on silver are extremely complex. Improving neutrality can only be achieved at the expense of selectivity.

[0016] The invention aims to obtain selective materials and glazing, neutral in reflection and neutral in transmission.

[0017] To characterize the color of a material or glazing in transmission, reflection or absorption, the reflection, transmission or absorption spectrum is determined. From this spectrum, the color can be defined by the parameters a* and b* in the Lab system with illuminant D65 and CIE 2° 1931 as observer.

[0018] In this case, a material or glazing that is too blue-green in appearance means that the a* values ​​are too negative. If we consider the colors in transmission, this means that the a*T values ​​are too negative.

[0019] Theoretically, seeking neutrality means aiming for zero a* and b* values. However, in practice, these results cannot be achieved. Furthermore, it is preferable not to be too close to 0 in order to avoid positive values. It is preferable to have a* values ​​less close to 0 but strictly negative rather than close to 0 but alternately positive or negative. In the latter case, undesirable changes in hue are observed, for example, between a little red and a little green. Therefore, if we do not want to be perfectly neutral, we prefer the color to tend towards blue-green rather than red.

[0020] To do this, we seek to obtain negative a* values ​​as close as possible to 0, particularly in transmission, and ideally for all observation angles. According to the invention, we can define different levels of neutrality in transmission depending on the transmission values ​​of a*T:

[0021] - Level 4: a*T between -8 and -6,

[0022] - Level 3: a*T between -6 and -4,

[0023] - Level 2: a*T between -4 and -2,

[0024] - Level 1: a*T between -2 and -0.

[0025] The more neutrality (level 1) is sought, the more negatively selectivity is impacted.

[0026] The values ​​of b*T can be positive or negative but preferably as close as possible to 0.

[0027] The applicant has discovered a new layered element that selectively absorbs in the green range, i.e. between 490 and 550 nm. The invention therefore relates to a new functional coating comprising two continuous silver-based functional metal layers and an absorbing layered element, which together achieve high selectivity and excellent color neutrality in transmission and reflection, at normal or angled incidence.

[0028] The behavior of the absorbing layered element of the invention is different from the visible absorbing elements traditionally used in functional coatings, which are, for example, metal layers or layers based on metal nitrides. These layers do not absorb specifically in the green but relatively homogeneously over the entire visible range (350-750 nm). Consequently, they do not allow the green color to be selectively neutralized. These absorbing layers do not allow both high selectivity and good neutrality to be obtained.

[0029] By selectively absorbing in the green, the effect of red color absorption is neutralized without too much impact on light transmission and therefore without reducing selectivity. The use of the absorbing layered element according to the invention, at an equal level of selectivity, makes it possible to obtain better neutrality.

[0030] The mechanism is as follows. In the absence of an element specifically absorbing the green color, to become less green we are forced to "enlarge" the transmission window towards red to capture more. In doing so, we let through a lot of red / infrared rays which significantly increase the solar factor and therefore reduce selectivity.

[0031] The behavior of the layered element according to the invention is also different from the layered elements based on discontinuous layers described in the prior art.

[0032] Document WO2018 / 197821 describes colored glazing composed of a clear glass substrate on which a colored coating is deposited. The coating comprises metal nanoparticles in an inorganic matrix of an oxide of at least one element chosen from the group of titanium, silicon, zirconium, for example TiOx:Ag. The colored coating has an absorption peak whose maximum is between 350 and 800 nm. The position of the maximum of the absorption peak varies according to the thickness of the colored coating, the oxidation levels or the density of the metal particles.

[0033] Document WO2019 / 239312 discloses functional coatings comprising a discontinuous silver layer encapsulated in an inorganic matrix based on niobium or silicon oxide.

[0034] WO2011 / 123402 discloses functional coatings comprising a discontinuous silver layer located between a zinc stannate dielectric layer and a nickel and chromium alloy ("Inconel") based layer or between a zinc oxide layer and a titanium layer.

[0035] These documents all disclose different layered elements comprising a discontinuous silver layer comprising nano-shaped silver particles encapsulated in different environments such as an inorganic matrix or two dielectric and / or metallic layers. These layered elements do not simply allow satisfactory absorption properties in the green, both before and after heat treatment.

[0036] Finally, nothing in these documents indicates how to modulate absorption in the preferred range between 475 and 590 nm.

[0037] The layered element of the invention comprises a discontinuous silver layer comprising silver nanoparticles capable of generating a plasmonic effect. The plasmonic effect consists of a vibration of the electron cloud of nanoparticles when they are subjected to an electromagnetic field. By "plasmonic absorption" is meant an absorption linked to plasmonic resonance effects of silver nanoparticles in a dielectric matrix. The particular absorption of the layered element according to the invention results from the plasmonic effect generated by the interactions between these nanoparticles and their specific environment. This new layered element specifically absorbs the green color. It is therefore particularly suitable for use in functional coatings with several continuous silver layers.

[0038] The invention therefore relates to a material comprising a transparent substrate coated with a functional coating comprising successively from the substrate an alternation of two continuous silver-based functional metal layers called, starting from the substrate, first and second functional layers, and three dielectric coatings called, starting from the substrate, Di1, Di2 and Di3, each dielectric coating comprising at least one dielectric layer, so that each continuous functional metal layer is arranged between two dielectric coatings, the dielectric coating Di1 and / or the dielectric coating Di2 comprises a layered element comprising:

[0039] - a first layer comprising silicon chosen from a layer of nitride, oxide or oxynitride,

[0040] - a discontinuous silver-based layer deposited directly on the first silicon-based layer comprising nanometric silver particles,

[0041] - a second layer comprising silicon chosen from a layer of nitride, oxide or oxynitride deposited directly on the discontinuous silver-based layer.

[0042] According to one embodiment:

[0043] - the first or second layer comprising silicon comprises oxygen, and

[0044] - the first or second layer comprising silicon comprises nitrogen. According to this definition, the two layers in contact with the discontinuous silver-based layer cannot be two layers of silicon oxide or two layers of silicon nitride. According to the invention, the layered element is judiciously placed in the first or second dielectric coating. The absorbing layered element placed in these dielectric coatings makes it possible to obtain high selectivity coupled with the desired aesthetics, i.e. excellent color neutrality in transmission and reflection, regardless of the viewing angle.

[0045] The preferred characteristics which appear in the remainder of the description are applicable both to the material according to the invention and, where appropriate, to the glazing, devices or method according to the invention.

[0046] Unless otherwise stated, thicknesses referred to in this document are physical thicknesses and layers are thin layers. A thin layer is defined as a layer with a thickness between 0.1 nm and 100 micrometers.

[0047] In this description, unless otherwise indicated, the expression "based on", used to qualify a material or a layer as to what it contains, means that the mass fraction of the constituent that it comprises is at least 50%, in particular at least 70%, preferably at least 90%.

[0048] Throughout the description, the substrate according to the invention is considered to be laid horizontally. The coating or layered element is deposited above the substrate. The meaning of the expressions "above" and "below" and "lower" and "upper" is to be considered in relation to this orientation. In the absence of a specific stipulation, the expressions "above" and "below" do not necessarily mean that two layers and / or coatings are arranged in contact with each other. When it is specified that a layer is deposited "in contact" with another layer or coating, this means that there cannot be one (or more) layer(s) interposed between these two layers (or layer and coating).

[0049] The coating is deposited by magnetic field-assisted sputtering (magnetron process). In this advantageous embodiment, all layers of the coating or layered element are deposited by magnetic field-assisted sputtering.

[0050] All the luminous characteristics described are obtained according to the principles and methods of the European standard EN 410 relating to the determination of luminous and solar characteristics of glazing used in glass for construction. Sunlight entering a building is considered to go from the outside to the inside.

[0051] The following luminous characteristics are measured according to illuminant D65 at 2° perpendicular to the material:

[0052] - AL corresponds to the light absorption in the visible in %,

[0053] - a*abs and b*abs correspond to the absorption colors a* and b* in the L*a*b* system, after removing the contribution of the substrate, with the observer on the layer side, - TL corresponds to the light transmission in the visible in %,

[0054] - Rext corresponds to the external light reflection in the visible in %, observer on the external space side,

[0055] - Rint corresponds to the interior light reflection in the visible in %, observer side interior space,

[0056] - a*T and b*T correspond to the transmission colors a* and b* in the L*a*b* system,

[0057] - a*Rext and b*Rext correspond to the colors in reflection a* and b* in the L*a*b* system, observer on the exterior space side,

[0058] - a*Rint and b*Rint correspond to the reflected colors a* and b* in the L*a*b* system, observer side interior space.

[0059] To assess the angle neutrality, the angle colors corresponding to the a* and b* colors in the L*a*b* system at an angle of 60° according to illuminant D65 are also determined. The angle colors can be determined in transmission a*60°T and b*60°T, in exterior reflection a*60°Rext and b*60°Rext or interior a*60°Rint and b*60°Rint.

[0060] To characterize the absorption of the layered element, it is possible to determine its absorption colors. To do this, the layered element is deposited on a clear glass substrate of 4 to 6 mm. Its absorption spectrum is then determined and the colors are calculated in the Lab system with illuminant D65 and CIE 2° 1931 as observer. It is then possible to calculate the light absorption AL and the colorimetric parameters a*abs and b*abs specific to it.

[0061] According to the invention, the absorbing layered element must specifically absorb in the green without having too high a light absorption so as not to have too much impact on the light transmission and therefore the selectivity. Neutralization is considered to be good when the layered element has very negative a*abs values ​​and a light absorption of less than 15%. Preferably:

[0062] - a*abs is less than -5, or less than -10, and / or

[0063] - b*abs varies between -10 and +10, and / or

[0064] - AL is between 10 and 15%.

[0065] Another way to assess neutralization efficiency is to determine the neutralization factor, which is the product of light absorption AL and a*abs. The neutralization efficiency is proportional to the neutralization factor.

[0066] Different results are obtained depending on whether or not the layered element undergoes a high-temperature heat treatment. When the layered element undergoes a quenching-type heat treatment, neutralization factors of -100 can be obtained. When the layered element does not undergo a quenching-type heat treatment, neutralization factors of the order of -40 can be obtained. Preferably, the neutralization factor is less than -50, or even less than -100. The layered element of the invention may also have the following characteristics alone or in combination:

[0067] - the second layer comprising silicon is a layer of silicon oxynitride,

[0068] - the first layer comprising silicon is a layer of silicon oxynitride,

[0069] - the first layer comprising silicon comprises oxygen,

[0070] - the first and second layers comprising silicon both comprise oxygen and in that the first layer comprising silicon comprises a greater proportion of oxygen than the second layer comprising silicon,

[0071] - the first and second layers have a different chemical composition,

[0072] - the first and second layers have the same chemical composition,

[0073] - the first and second layers comprising silicon are layers based on silicon nitride,

[0074] - the first layer comprising silicon has a thickness of between 2 and 30 nm, between 4 and 20 nm, preferably 5 to 15 nm,

[0075] - the second layer comprising silicon has a thickness of between 2 and 30 nm, between 4 and 20 nm, preferably 5 to 15 nm,

[0076] - the discontinuous silver-based layer has a thickness of less than 5 nm, preferably less than 4.0 nm, less than 3.0 nm or less than 2.0 nm,

[0077] - the discontinuous silver-based layer deposited by cathode sputtering in an atmosphere comprising argon or krypton, preferably krypton,

[0078] - the layered element has an absorption peak in the visible range with a maximum between 490 and 550 nm, preferably between 500 and 525 nm,

[0079] - the layered element has an absorption peak in the visible range whose width at half-maximum is less than 350 nm, preferably less than 300 nm, or even less than 270 nm,

[0080] - the layered element has a visible light absorption of between 8 and 20%, preferably between 10 and 17%, absorption measured on the layered element side on a 4 mm thick clear glass substrate.

[0081] According to the invention, two layers of different chemical composition means that they are composed of different chemical elements or composed of the same elements in different proportions. According to the invention, two layers of the same chemical composition means that they are composed of the same chemical elements present in the same proportions.

[0082] The layered element has its advantageous absorption properties both:

[0083] - when the layered element or the substrate carrying the layered element has not undergone high temperature heat treatment and

[0084] - when the layered element or the substrate carrying the layered element undergoes heat treatment at high temperature. Obtaining the properties regardless of the presence or absence of heat treatment allows greater flexibility and simplicity in production lines. For example, it is possible to use the same cathode sequence for coatings used untempered and tempered.

[0085] According to the invention, the discontinuous silver particles are encapsulated between two particular dielectric layers which constitute the particular environment. The applicant has discovered that the advantageous absorption properties, before and after heat treatment, of the layered element of the invention result directly from this environment. Indeed, it is this environment comprising silicon, nitrogen and oxygen, in contact with the discontinuous silver-based layer, which makes it possible to have the maximum absorption in the green, in particular in the wavelength range from 490 to 550 nm.

[0086] Such a system not only allows for selective absorption of certain colors, but also for modulation of absorption properties in a favorable wavelength region. By selectively absorbing certain wavelengths, light transmission is less affected. This allows for maintaining high selectivity. Being able to modulate the position of the absorption peak on demand also makes it easier to control colors.

[0087] Another advantage of the layered element according to the invention is that the colors, in particular the b*abs values, can be adjusted by adapting the quantities of oxygen during the deposition of the layer(s) located below and / or above the silver particles. This color adjustment could not be achieved with the materials encapsulating the silver particles of the prior art. By varying the oxidation rate of the layers comprising silicon, trends have been identified. For example, by increasing the oxidation rate of the second layer comprising silicon, a shift from the very positive b*abs values ​​to less positive values ​​is observed without significant modification of the a*abs values, which remain negative. It is therefore possible to modulate the color very easily by simply varying the oxidation level of the second layer comprising silicon.

[0088] Another advantage of using such silicon-based layers is that they exhibit absorption parameters close to those sought even before or without heat treatment.

[0089] In order to show that the nature of the layers is an essential characteristic of the invention, other configurations were tested. Among these, configurations comprising metallic layers based on titanium or nickel-chromium alloy above the discontinuous silver layer and configurations comprising dielectric layers of a nature different from those claimed. These configurations have the following drawbacks: - excessive light absorption in the visible,

[0090] - an absorption peak absent or not centered between 490 and 550 nm, and / or

[0091] - unsatisfactory colors with absorption values ​​of a*abs not negative enough and b*abs too positive.

[0092] The layered element has a thickness:

[0093] - greater than or equal to 4 nm, greater than or equal to 5 nm, greater than or equal to 8 nm, greater than or equal to 10 nm or greater than or equal to 15 nm,

[0094] - less than or equal to 100 nm, less than or equal to 30 nm, less than or equal to 20 nm or less than or equal to 15 nm.

[0095] Preferably, the layered element has a thickness of between 5 nm and 15 nm. The thickness of the layered element corresponds to the sum of the thicknesses of the first and second layers comprising silicon and the equivalent thickness of the discontinuous silver-based layer.

[0096] The layered element comprises a discontinuous layer of silver. According to the invention, a layer of a material is considered to be continuous when the layer is present over the entirety of a surface and consists over the entirety of this surface of a non-zero thickness of the material considered. In contrast, a discontinuous layer is not present over the entirety of this surface.

[0097] The coverage rate characterizes this discontinuity. The coverage rate corresponds to the percentage ratio, in a square of any size on the surface of the material, of the area occupied by the discontinuous layer to the surface of the square. The discontinuous layer represents 10% to 63%, 10 to 60%, 10 to 50%, of the surface of the square.

[0098] For each material and depending on its environment, there is a minimum thickness below which the layer will not be continuous. For silver-based layers deposited by sputtering, the minimum thickness below which a continuous layer is not obtained is approximately 5 nm. This means that when we choose to configure the sputtering device by aiming for a continuous layer of 5 nm thickness, we actually obtain a discontinuous layer which will have areas without silver and areas with silver particles thicker than 5 nm. There is an arrangement in the form of nanometric silver particles then forming nanometric patterns.

[0099] The nanoparticles according to the invention are organized in a plane. This means that there are no multiple superimposed particles in the thickness of the discontinuous silver-based layer. The discontinuous silver-based layer is therefore of single-particle thickness. A complete characterization can therefore be carried out in a plane parallel to the substrate at the discontinuous layer. According to the invention, the nanometric silver particles (or nanoparticles) are encapsulated between two particular dielectric layers.

[0100] The applicant has discovered that the advantageous absorption properties, before and after heat treatment, of the layered element of the invention depend directly on this environment. Indeed, this environment, in contact with the discontinuous silver-based layer, allows for maximum absorption in the green, particularly in the wavelength range from 490 to 550 nm.

[0101] The applicant also discovered that the morphology and distribution of the nanoscale silver particles also strongly influence the resonance and absorption properties. Among the influencing characteristics are:

[0102] - the size of the nanoparticles,

[0103] - the density of nanoparticles,

[0104] - surface filling,

[0105] - the interparticle distance,

[0106] - the shape such as the aspect ratio and

[0107] - the height of the nanoparticles.

[0108] The characterization of the morphology of the discontinuous layer can be carried out by any microscopic observation mode, direct or indirect, such as scanning electron microscopy, transmission electron microscopy (TEM), electron backscatter diffraction, atomic force microscopy and optical microscopy.

[0109] Preferably, the characterization of the morphology of the discontinuous layer is determined by quantitative statistical analysis of TEM images. This image analysis can be carried out using scikit-image, which is an image processing library in Python. The TEM images allow a statistical study of the morphology of the nanoparticles. From these images, the following information can be extracted: the area occupied by a particle and its equivalent diameter, its principal axes, the position of its center, the number of particles per image, the total area occupied by all the particles. The area occupied by all the particles gives the surface filling or occupancy rate.

[0110] The size of nanoparticles is estimated by calculating the equivalent particle diameter. To do this, the surface area of ​​each particle is determined. Then, the equivalent diameter of a disk with the same surface area is calculated. Finally, the median of all particles counted in the image is determined to obtain the median equivalent diameter.

[0111] The density of nanoparticles is determined by counting the number of particles per image and reporting this value per pm 2 surface (particles. pm -2 ). The surface filling or occupancy rate corresponds to the percentage of area occupied by all the particles on the area of ​​the total discontinuous layer (particles and discontinuity).

[0112] The interparticle distance is the distance between two particle centers. The median interparticle distance is the median of all interparticle distances.

[0113] The aspect ratio corresponds for each particle to the ratio of the major axis to the minor axis. It characterizes the elongation of a particle with a value greater than 1.

[0114] The height of nanoparticles (hnp) is determined, to first order assuming that the particles have straight edges, from the equivalent thickness and the surface filling with hnp = Eq. thickness / Surface filling.

[0115] The discontinuous layer or nanoparticles exhibit the following properties alone or in combination:

[0116] - particle density greater than 1x10 3 or between 1x10 3 and 9x10 4 particles*prrr 2 , between 5x10 3 and 5x10 4 particles*prrr 2 , preferably between 8x10 3 and 4x10 4 particles*pm -2 , and / or

[0117] - the surface filling of the discontinuous layer by the nanoparticles is between 10 and 60%, between 10 and 50%, preferably between 25 and 40%, and / or

[0118] - the median equivalent diameter is between 1 and 10 nm, between 2 and 8 nm, preferably between 3 and 5 nm, and / or

[0119] - the median interparticle distance is between 3 and 10 nm, between 4 and 8 nm, preferably between 4 and 7 nm, and / or

[0120] - the median aspect ratio is between 1 and 2, preferably between 1 and 1.5, and / or

[0121] - the equivalent height of the nanoparticles is between 1 and 5 nm, preferably between 1 and 3.5 nm.

[0122] According to the invention, the equivalent thickness of a discontinuous layer is defined as the thickness of this layer if it were continuous. This equivalent thickness can, for example, be approximated by an analysis of the layered element by microprobe secondary ion mass spectrometry ("SIMS"). This makes it possible to quantify the quantity of material in number of silver atoms per unit area. This value can then be converted into equivalent thickness. To obtain an equivalent thickness, the corresponding thickness is determined for a low running speed. Then, a rule of 3 is applied to the running speed to obtain the desired equivalent thickness. For example, a thickness of 10 nm is measured for a silver layer deposited at a running speed of 1 m / min. Consequently, if we wish to obtain a silver layer with an equivalent thickness of 1 nm, we will choose a running speed of 10 m / min.

[0123] The discontinuous silver-based layer has an equivalent thickness:

[0124] - greater than 0.3 nm, greater than 0.5 nm, greater than 0.8 nm, greater than 1.0 nm, and / or - less than 5 nm, less than 4.5 nm, less than 4.0 nm, less than 3.0, less than 2.5 nm, less than 2.0 nm, less than 1.5 nm, less than 1.0 nm.

[0125] The silver-based discontinuous layer comprises at least 95.0%, preferably at least 96.5% and more preferably at least 98.0% by mass of silver relative to the mass of the discontinuous layer. Preferably, the silver-based discontinuous layer comprises less than 1.0% by mass of metals other than silver relative to the mass of the silver-based functional metal layer. To have a sharp absorption peak, it is preferable to have discontinuous layers of pure or lightly doped silver. The silver particles are preferably based on pure silver.

[0126] The discontinuous layer is deposited above and in contact with a first layer comprising silicon and below and in contact with a second layer comprising silicon.

[0127] Each layer comprising silicon in contact with the discontinuous silver-based layer has a thickness greater than or equal to 2 nm, greater than or equal to 3 nm, greater than or equal to 4 nm or greater than or equal to 5 nm.

[0128] Each layer comprising silicon in contact with the discontinuous silver-based layer has a thickness less than or equal to 25 nm, less than or equal to 20 nm or less than or equal to 15 nm.

[0129] The layers comprising silicon may be selected from silicon oxide-based, silicon nitride-based or silicon oxynitride-based layers such as silicon oxide-based layers, silicon nitride-based layers and silicon oxynitride-based layers.

[0130] The amounts of oxygen and nitrogen in a layer are determined as atomic percentages relative to the total amounts of oxygen and nitrogen in the layer under consideration.

[0131] According to the invention:

[0132] - silicon oxide-based layers consist mainly of oxygen and very little nitrogen,

[0133] - silicon nitride-based layers consist mainly of nitrogen and very little oxygen,

[0134] - silicon oxynitride-based layers include a mixture of oxygen and nitrogen.

[0135] The silicon oxide-based layers comprise at least 90 atomic percent oxygen relative to the oxygen and nitrogen in the silicon oxide-based layer. The silicon nitride-based layers comprise at least 90 atomic percent nitrogen relative to the oxygen and nitrogen in the silicon nitride-based layer. The silicon oxynitride-based layers comprise 10 to 90 atomic percent nitrogen relative to the oxygen and nitrogen in the silicon oxynitride-based layer. In one embodiment, both the first and second silicon-comprising layers comprise oxygen. Preferably, the first silicon-comprising layer comprises a greater proportion of oxygen than the second silicon-comprising layer.This means, for example, that the atomic percentage of oxygen relative to oxygen and nitrogen in the first layer comprising silicon is 5%, or even 10%, or even 20% higher than the atomic percentage of oxygen relative to oxygen and nitrogen in the second layer comprising silicon.

[0136] The color of the layered element is changeable within a certain advantageous range by changing the oxidation rate of the first and second layers comprising silicon and / or the thickness of the discontinuous silver layer.

[0137] To illustrate this phenomenon simply, we will use layers comprising 100% by mass of silicon relative to the mass of all the elements constituting the layer comprising silicon other than nitrogen and oxygen. However, the invention is not limited to the exclusive presence of silicon. The layer may comprise other elements.

[0138] The composition of the first and second layer comprising silicon in contact with the discontinuous silver-based layer can vary stochiometrically between SiC>2 and SisN4 through oxynitrided layers. Such layers comprising silicon can be defined by the formula SiON(x) = x Si3N4 + (1-x) SiC>2 with the parameter x characteristic of the effective mixture between 0 and 1.

[0139] Stoichiometry is assessed using the optical index at 550 nm (2.0 for SiN, 1.5 for SiO2). The amount of nitrogen N2 is kept more or less constant. It is the amount of O2 that determines the oxidation rate of the layer.

[0140] The first layer comprising silicon preferably has a parameter x which varies between 0 and 0.5 or between 0.1 and 0.4.

[0141] The second layer comprising silicon preferably has a parameter x which varies between 0.2 and 1, between 0.1 and 1 or between 0.2 and 0.9.

[0142] By varying the oxynitriding of these two layers, it is possible to shift the maximum absorption peak. By doing this, the colors can be modified on demand.

[0143] In the case of a non-heat-treated material, there is a thickness range for the discontinuous silver layer where the a*abs in absorption is negative and stable. On the other hand, when the thickness of the silver layer is increased:

[0144] - the neutralization potential (AL*a*abs) increases because the light absorption AL increases,

[0145] - the b*abs increases which may not be desired for the stack colors. To prevent the increase in b*abs, it is possible to increase the oxidation rate of the second layer containing silicon. This has the effect of decreasing the b*abs and therefore modifying the color rendering. Finally, the absorption peak is sharper when the oxidation rate of the first layer containing silicon is high.

[0146] In the case of a heat-treated material, the heat treatment helps to refine the absorption peak. The higher the oxidation rate in the first and second layers containing silicon, the more the peak becomes refined and shifts towards the blue (compared to the non-heat-treated material). This makes it possible to adjust the b*abs and have a very negative a*abs. On the other hand, if there is too much oxygen, the light absorption AL becomes too low and the neutralization insufficient.

[0147] The layers comprising silicon comprising at least 90% by mass of silicon relative to the mass of all the elements constituting the layer comprising silicon other than nitrogen and oxygen have, depending on whether they are oxide, nitride or oxynitride layers, refractive indices as defined below. The layers based on silicon oxide are characterized by a refractive index at 550 nm, less than or equal to 1.55. The layers based on silicon nitride are characterized by a refractive index at 550 nm, greater than or equal to 1.95. The layers based on silicon oxynitride are characterized by a refractive index at 550 nm intermediate between a non-nitrided oxide layer and a non-oxidized nitride layer. The silicon oxynitride-based layers preferably have a refractive index at 550 nm greater than 1.55, 1.60 or 1.70 or between 1.55 and 1.95, 1.60 and 2.00, 1.70 and 2.00 or 1.70 and 1.90.These refractive indices can vary to a certain extent (± 0.1) depending on the deposition conditions. Indeed, by adjusting certain parameters such as pressure or the presence of dopants, it is possible to obtain more or less dense layers and therefore a variation in the refractive index.

[0148] The layers comprising silicon may comprise or consist of elements other than silicon, oxygen and nitrogen. These elements may be selected from aluminum, boron, titanium, and zirconium.

[0149] The silicon-comprising layers may comprise at least 50%, at least 60%, at least 65%, at least 70%, at least 75.0%, at least 80% or at least 90% by mass of silicon relative to the mass of all elements constituting the silicon-comprising layer other than nitrogen and oxygen.

[0150] Preferably, the layer comprising silicon comprises at most 35%, at most 20% or at most 10% by mass of elements other than silicon relative to the mass of all the elements constituting the layer comprising silicon other than oxygen and nitrogen.

[0151] The layer comprising silicon may comprise at least 2%, at least 5.0% or at least 8% by mass of aluminum relative to the mass of all elements constituting the silicon oxide-based layer other than oxygen and nitrogen.

[0152] Silicon nitride and zirconium Si-based layers x Zr y N z are part of the layers comprising silicon, in particular layers based on silicon nitride. The refractive index of the layers based on silicon nitride and zirconium increases with increasing proportions of zirconium in said layer.

[0153] Silicon nitride-based layers may comprise aluminum and / or zirconium. Such layers may comprise, in atomic proportions relative to the atomic proportions of Si, Zr and Al:

[0154] - 50 to 98%, 60 to 90%, 60 to 70% atomic silicon,

[0155] - 0 to 10%, 2 to 10% atomic aluminum,

[0156] - 0 to 30%, 10 to 40% or 15 to 30% atomic zirconium.

[0157] According to the invention, the first and second layers comprising silicon are deposited from a silicon metal target. The deposition is carried out in an atmosphere comprising an optimized quantity of oxygen and nitrogen to obtain the desired properties. The deposition atmosphere comprises a mixture of noble gas (He, Ne, Xe, Ar, Kr) and oxygen and / or nitrogen. The noble gas is preferably argon. The following parameters are used to define the conditions for a cathode sputtering deposition:

[0158] - the deposition pressure,

[0159] - the composition of the gases in volume flow (unit sccm “standard cubic centimeter per minute”). According to the invention, the following parameters were used:

[0160] - the pressure in the deposition chamber is between 1 and 15 pbar, preferably 2 and 10 pbar or 2 and 8 pbar,

[0161] - the deposition atmosphere includes a mixture of argon and oxygen and nitrogen.

[0162] The optimal oxygen threshold may vary to some extent depending on, for example:

[0163] - power,

[0164] - the configuration of the sputtering deposition chamber (geometry, locations of gas inlets, etc.)

[0165] A person skilled in the art is able to define a satisfactory atmosphere by varying these parameters to a certain extent. In particular, a person skilled in the art is perfectly able to determine the power to be applied to the target and the volume flow rates of oxygen, nitrogen and noble gases.

[0166] Unless otherwise stated, the thicknesses mentioned in this document without further details are physical, real or geometric thicknesses called Ep and are expressed in nanometers (and not optical thicknesses). The optical thickness Eo is defined as the physical thickness of the layer considered multiplied by its refractive index at the wavelength of 550 nm: Eo = n*Ep. Since the refractive index is a dimensionless value, the unit of optical thickness can be considered to be that chosen for the physical thickness.

[0167] According to the invention, a dielectric coating corresponds to a sequence of layers comprising at least one dielectric layer, located between the substrate and the first functional layer (DU), between two functional layers (Di2 or Di3) or above the last functional layer (Di4).

[0168] If a dielectric coating is composed of several dielectric layers, the optical thickness of the dielectric coating corresponds to the sum of the optical thicknesses of the different dielectric layers constituting the dielectric coating. If a dielectric coating includes an absorbing layer for which the refractive index at 550 nm includes an imaginary part of the dielectric function that is not zero (or not negligible), for example a metal layer, the thickness of this layer is not taken into account for the calculation of the optical thickness of the dielectric coating.

[0169] The thickness of the blocking layers is not taken into account for the calculation of the optical thickness of the dielectric coating.

[0170] When a dielectric coating comprises a layered element, the thickness of the dielectric layers of the layered element are taken into account in calculating the optical or physical thickness of the dielectric coating.

[0171] For the purposes of the present invention, the terms "first", "second", and "third" for the functional layers or dielectric coatings are defined starting from the substrate carrying the stack and referring to the layers or coatings of the same function. For example, the functional layer closest to the substrate is the first functional layer, the next one away from the substrate is the second functional layer, etc.

[0172] The functional coating comprises two continuous silver-based metal functional layers (F1 and F2), each disposed between two dielectric coatings (Di1, Di2, Di3). The functional coating may comprise only two continuous silver-based metal functional layers.

[0173] The continuous silver-based metal functional layers comprise at least 95.0%, preferably at least 96.5% and more preferably at least 98.0% by mass of silver relative to the mass of the functional layer. Preferably, a silver-based metal functional layer comprises less than 1.0% by mass of metals other than silver relative to the mass of the silver-based metal functional layer.

[0174] The first functional layer has a thickness between 7 and 20 nm or between 10 and 18 nm. The second functional layer has a thickness between 7 and 20 nm or between 10 and 18 nm.

[0175] The functional coating comprises one or more layers of blocking located in contact below and / or above one or more functional layers.

[0176] Blocking layers traditionally serve to protect the functional layers from possible degradation during the deposition of the upper dielectric coating and during possible high-temperature heat treatment, such as annealing, bending and / or quenching.

[0177] The blocking layers are chosen from:

[0178] - metallic layers based on a metal or a metallic alloy, metallic nitride layers, and metallic oxynitride layers of one or more elements chosen from titanium, zinc, tin, nickel, chromium and niobium,

[0179] - metal oxide layers of one or more elements chosen from titanium, nickel, chromium and niobium.

[0180] The blocking layers may in particular be layers of Ti, TiN, TiOx, Nb, NbN, Ni, NiN, Cr, CrN, NiCr, NiCrN, SnZnN. When these blocking layers are deposited in metallic, nitrided or oxynitrided form, these layers may undergo partial or total oxidation depending on their thickness and the nature of the layers surrounding them, for example, at the time of deposition of the following layer or by oxidation in contact with the underlying layer.

[0181] According to advantageous embodiments of the invention, the blocking layer(s) satisfy one or more of the following conditions:

[0182] - each functional metal layer is in contact with at least one blocking layer chosen from a blocking sub-layer and a blocking over-layer, and / or

[0183] - each functional metal layer is in contact with a blocking overlayer, and / or

[0184] - the thickness of each blocking layer is at least 0.05 nm, or between 0.05 and 2.0 nm or between 0.05 and 1 nm, and / or

[0185] - the sum of the thicknesses of all blocking layers is greater than or equal to 0.5 nm or greater than or equal to 0.8 nm or greater than or equal to 1.0 nm, and / or

[0186] - the sum of the thicknesses of all blocking layers is less than or equal to 5.0 nm or less than or equal to 3.0 nm or less than or equal to 2.0 nm,

[0187] For blocking layers, the thicknesses correspond to the thicknesses of the layers as deposited, i.e. before heat treatment or before possible oxidation during deposition of the overlying layer.

[0188] According to the invention, the blocking layers are considered not to be part of a dielectric coating. This means that their thickness is not taken into account in the calculation of the optical or geometric thickness of the dielectric coating located in contact with them.

[0189] By "dielectric layer" within the meaning of the present invention, it is to be understood that from the point of view of its nature, the material is "non-metallic", that is to say is not a metal. In the context of the invention, this term designates a material having an n / k ratio over the entire visible wavelength range (from 380 nm to 780 nm) equal to or greater than 5. Preferably, each dielectric coating consists solely of one or more dielectric layers. Preferably, there is therefore no absorbing layer in the dielectric coatings so as not to reduce the light transmission.

[0190] By "dielectric coating" within the meaning of the present invention, it is understood that there may be a single layer or several layers of different materials inside the coating. A "dielectric coating" according to the invention mainly comprises dielectric layers. However, according to the invention these coatings may also comprise layers of other nature, in particular absorbent layers, for example metallic ones.

[0191] A "same" dielectric coating is considered to be located:

[0192] - between the substrate and the first functional layer,

[0193] - between each functional silver-based metal layer,

[0194] - above the last functional layer (furthest from the substrate).

[0195] By "dielectric layer" for the purposes of the present invention, it is to be understood that from the point of view of its nature, the material is "non-metallic", i.e. is not a metal. In the context of the invention, this term designates a material having an n / k ratio over the entire visible wavelength range (from 380 nm to 780 nm) equal to or greater than 5. n designates the real refractive index of the material at a given wavelength and k represents the imaginary part of the refractive index at a given wavelength; the n / k ratio being calculated at a given wavelength identical for n and for k.

[0196] The thickness of a dielectric coating corresponds to the sum of the thicknesses of the layers constituting it.

[0197] The coatings have a thickness greater than 15 nm, preferably between 15 and 200 nm.

[0198] The dielectric layers of the coatings have the following characteristics alone or in combination:

[0199] - they are deposited by magnetic field-assisted cathode sputtering,

[0200] - they are chosen from oxides, nitrides or oxynitrides of one or more elements chosen from titanium, silicon, aluminum, zirconium, tin and zinc,

[0201] - they have a thickness greater than 2 nm, preferably between 4 and 100 nm.

[0202] Dielectric layers, in addition to their optical function, can have various other functions. The choice of the nature and position of the dielectric layers within the dielectric coating depends on this function. For example, the following functions can be cited:

[0203] - stabilizer or wetting layers located in the immediate vicinity of silver-based functional layers such as zinc oxide-based layers,

[0204] - smoothing layers located below the wetting layers such as tin oxide-based layers,

[0205] - barrier or optical function layers.

[0206] A single dielectric layer generally performs several functions. In fact, each dielectric layer plays an optical role which depends on its refractive index and its thickness.

[0207] The dielectric layers are conventionally chosen from oxide-based, nitride-based or oxynitride-based layers. The oxide-based layers of one or more elements comprise essentially oxygen and very little nitrogen. The oxide-based layers comprise in particular at least 90% by atomic percentage of oxygen relative to the oxygen and nitrogen in said layer. The nitride-based layers comprise essentially nitrogen and very little oxygen. The nitride-based layers comprise at least 90% by atomic percentage of nitrogen relative to the oxygen and nitrogen in said layer. The oxynitride-based layers comprise a mixture of oxygen and nitrogen. The silicon oxynitride-based layers comprise 10 to 90% (limits excluded) by atomic percentage of nitrogen relative to the oxygen and nitrogen in said layer.

[0208] The amounts of oxygen and nitrogen in a layer are determined as atomic percentages relative to the total amounts of oxygen and nitrogen in the layer under consideration.

[0209] The dielectric layers are classically chosen from:

[0210] - layers comprising silicon, aluminum and / or zirconium, optionally doped with at least one other element,

[0211] - tin oxide-based layers,

[0212] - layers based on titanium oxide,

[0213] - zinc oxide-based layers.

[0214] Preferably, the silver-based functional layer is located above a dielectric layer called a stabilizing or wetting layer made of a material capable of stabilizing the interface with the functional layer. These layers are generally based on zinc oxide.

[0215] Preferably, the silver-based functional layer is located below a dielectric layer called a stabilizing or wetting layer made of a material capable of stabilizing the interface with the functional layer. These layers are generally based on zinc oxide.

[0216] The zinc oxide-based layers may comprise at least 80% or at least 90% by mass of zinc relative to the total mass of all the elements constituting the zinc oxide-based layer excluding oxygen and nitrogen.

[0217] The zinc oxide-based layers may comprise one or more elements selected from aluminum, titanium, niobium, zirconium, magnesium, copper, silver, gold, silicon, molybdenum, nickel, chromium, platinum, indium, tin and hafnium, preferably aluminum. The zinc oxide-based layers may optionally be doped with at least one other element, such as aluminum.

[0218] A priori, the zinc oxide-based layer is not nitrided, however traces may exist.

[0219] The zinc oxide-based layer comprises, in order of increasing preference, at least 80%, at least 90%, at least 95%, at least 98% or at least 100%, by mass of oxygen relative to the total mass of oxygen and nitrogen.

[0220] The dielectric coating located between the substrate and the first functional metal layer and / or one or each dielectric coating located above the first silver-based functional layer comprises a zinc oxide-based layer comprising at least 80% by mass of zinc relative to the mass of all elements other than oxygen.

[0221] Preferably, each dielectric coating comprises a zinc oxide-based layer comprising at least 80% by mass of zinc relative to the mass of all elements other than oxygen.

[0222] Preferably, the dielectric coatings located directly below a continuous silver-based functional metal layer comprise at least one zinc oxide-based dielectric layer, optionally doped with at least one other element, such as aluminum. The metal functional layer deposited above a zinc oxide-based layer is either directly in contact or separated by a blocking layer.

[0223] Preferably, the dielectric coatings located directly above a continuous silver-based functional metal layer comprise at least one zinc oxide-based dielectric layer, optionally doped with at least one other element, such as aluminum. The metal functional layer deposited below a zinc oxide-based layer is either directly in contact or separated by a blocking layer.

[0224] The zinc oxide layers have a thickness:

[0225] - at least 1.0 nm, at least 2.0 nm, at least 3.0 nm, at least 4.0 nm or at least 5.0 nm, and / or

[0226] - not more than 25 nm, not more than 10 nm or not more than 8.0 nm.

[0227] Preferably, the material comprises one or more layers based on tin oxide, preferably zinc oxide and tin.

[0228] The tin oxide-based layers comprise at least 20% by mass of tin relative to the mass of elements other than oxygen or nitrogen. The zinc and tin oxide-based layers comprise at least 20% by mass of tin relative to the total mass of zinc and tin. The zinc and tin oxide-based layer comprises, relative to the total mass of zinc and tin, at least 20%, at least 30%, at least 40%, at least 50%, at least 60% or at least 80% by mass of tin. Preferably, the zinc and tin oxide-based layer comprises 40 to 80% by mass of tin relative to the total mass of zinc and tin.

[0229] The tin oxide layer has a thickness:

[0230] - greater than 5 nm, greater than 10 nm, greater than 15 nm, greater than 20 nm or greater than 25 nm,

[0231] - less than 50 nm, less than 40 nm or less than 35 nm.

[0232] The dielectric coating located between the substrate and the first continuous functional metal layer and / or one or each dielectric coating located above the first continuous silver-based functional layer comprises a layer based on tin oxide, preferably zinc oxide and tin comprising at least 20% by mass of tin relative to the total mass of zinc and tin. Each dielectric coating may comprise a layer of tin oxide, preferably based on zinc oxide and tin comprising at least 20% by mass of tin relative to the total mass of zinc and tin.

[0233] The dielectric coatings may comprise layers comprising silicon as defined for the layered element.

[0234] Each layer comprising silicon has a thickness greater than or equal to 2 nm, greater than or equal to 3 nm, greater than or equal to 4 nm or greater than or equal to 5 nm.

[0235] Each layer comprising silicon has a thickness less than or equal to 25 nm, less than or equal to 20 nm or less than or equal to 15 nm.

[0236] Layers containing silicon can be obtained:

[0237] - by cathode sputtering,

[0238] - from a silicon metal target or a silicon oxide ceramic target.

[0239] The dielectric coating furthest from the substrate may comprise a protective layer. These layers generally have a thickness of between 0.5 and 10 nm, preferably 1 and 5 nm. This protective layer may be chosen from a layer based on titanium, zirconium, hafnium, silicon, zinc and / or tin and their mixture, this or these metals being in metallic, oxidized or nitrided form.

[0240] The functional coating advantageously has one or more of the following characteristics:

[0241] - each dielectric coating located below a functional layer comprises a zinc oxide-based layer located below, in contact with or separated by a blocking layer, the functional layer having a thickness greater than or equal to 3 nm,

[0242] - each dielectric coating located above a functional layer comprises a zinc oxide-based layer located above, in contact with or separated by a blocking layer, from the functional layer,

[0243] - the first functional layer has a thickness between 7 and 20 nm,

[0244] - the second functional layer has a thickness between 7 and 20 nm, - the first dielectric coating Di 1 has an optical thickness between 60 and 120 nm,

[0245] - the second dielectric coating Di2 has an optical thickness between 120 and 250 nm,

[0246] - the third dielectric coating Di3 has an optical thickness between 40 and 120 nm.

[0247] The dielectric coatings of the functional coating may have the following characteristics alone or in combination: the first dielectric coating Di 1 comprises in this order:

[0248] - a layer based on silicon nitride or titanium oxide from 0 to 20 nm,

[0249] - the layered element,

[0250] - a layer based on zinc and tin oxide from 0 to 15 nm,

[0251] - a zinc oxide-based layer of 2 to 12 nm, the second dielectric coating Di2 comprises in this order:

[0252] - a zinc oxide-based layer of 2 to 12 nm,

[0253] - a layer based on silicon nitride of 15 to 100 nm,

[0254] - a layer based on zinc and tin oxide from 0 to 20 nm,

[0255] - a zinc oxide-based layer of 2 to 12 nm, the third dielectric coating Di3 comprises in this order:

[0256] - a zinc oxide-based layer of 2 to 12 nm,

[0257] - one or more layers based on silicon nitride, the thickness of all these layers based on silicon nitride is 15 to 75 nm or 20 to 45 nm,

[0258] - a top protective layer of 0 to 5 nm, all these thicknesses being physical thicknesses.

[0259] The dielectric coatings of the functional coating may have the following characteristics alone or in combination: the first dielectric coating Di 1 comprises in this order:

[0260] - a layer based on silicon nitride or titanium oxide of 20 to 50 nm,

[0261] - a layer based on zinc and tin oxide from 0 to 30 nm,

[0262] - a zinc oxide-based layer of 2 to 24 nm, the second dielectric coating Di2 comprises in this order:

[0263] - a zinc oxide-based layer of 4 to 24 nm,

[0264] - a layer based on silicon nitride of 30 to 100 nm,

[0265] - a silicon oxide-based layer from 0 to 30 nm,

[0266] - the layered element,

[0267] - a layer based on silicon nitride of 30 to 100 nm,

[0268] - a layer based on zinc and tin oxide from 0 to 40 nm,

[0269] - a zinc oxide-based layer of 4 to 24 nm, - the third dielectric coating Di3 comprises in this order:

[0270] - a zinc oxide-based layer of 4 to 24 nm,

[0271] - one or more layers based on silicon nitride, the thickness of all these layers based on silicon nitride is 30 to 75 nm or 20 to 45 nm,

[0272] - a top protective layer of 0 to 5 nm, all these thicknesses being optical thicknesses.

[0273] According to one embodiment, the protective layer is based on zirconium and / or titanium oxide, preferably based on zirconium oxide, titanium oxide or titanium and zirconium oxide.

[0274] The material, i.e., the coated transparent substrate, is intended to undergo heat treatment at high temperature. Therefore, the coating and the substrate have preferably been subjected to heat treatment at a high temperature such as quenching, annealing or bending.

[0275] The material of the invention has the advantage that these advantageous properties are obtained even when the material coated with the functional coating or the functional coating alone has not undergone heat treatment at high temperature. The materials according to the invention can be used indifferently:

[0276] - as deposited, i.e. without having been subjected to any heat treatment at high temperature, in this case neither the substrate coated with the functional coating, nor the functional coating alone, has undergone heat treatment at high temperature,

[0277] - treated by laser radiation, in this case only the functional coating undergoes heat treatment at high temperature,

[0278] - treated by annealing or quenching, in this case the substrate and the functional coating undergo heat treatment at high temperature.

[0279] As explained above, according to the invention the properties must be obtained even when the functional coating or the substrate carrying the functional coating has not undergone heat treatment at high temperature.

[0280] The present invention therefore relates to the non-heat-treated coated substrate. The functional coating may not have undergone heat treatment at a temperature above 500°C, preferably 300°C.

[0281] The present invention also relates to the heat-treated material. The heat treatments are chosen from:

[0282] - annealing, for example rapid annealing,

[0283] - quenching and / or bending.

[0284] The material, i.e., the transparent substrate coated with the functional coating, may have undergone heat treatment at elevated temperature. The functional coating and the substrate may have undergone heat treatment at elevated temperature such as quenching, annealing, or bending.

[0285] It is also possible to heat treat only the stack. In this case, only the functional coating may have undergone heat treatment.

[0286] In both cases, the functional coating may have undergone heat treatment at a temperature above 300°C, preferably 500°C. The heat treatment temperature (at the functional coating) is above 300°C, preferably above 400°C, and more preferably above 500°C.

[0287] According to the invention, it is possible to carry out a rapid thermal annealing process (Rapid Thermal Process) such as laser or flash lamp annealing. Rapid thermal annealing is described, for example, in applications WO2008 / 096089 and WO2015 / 185848. In these cases, only the functional coating is subjected to heat treatment. During this type of treatment, each point of the stack is heated to a temperature of at least 300°C while maintaining a temperature less than or equal to 150°C at any point on the face of the substrate opposite that on which the functional coating is located. This process has the advantage of heating only the functional coating, without significant heating of the entire substrate.

[0288] In the case of laser processing, the coated materials can be treated using a laser line formed from laser sources such as InGaAs laser diodes or Yb:YAG disk lasers. These continuous sources emit at a wavelength between 900 and 1100 nm. The laser line has a length of about 3.3 m, equal to the width 1 of the substrate, and an average full width at half maximum FWHM between 45 and 100 pm.

[0289] The materials are arranged on a roller conveyor so as to travel in an X direction, parallel to its length. The laser line is fixed and positioned above the coated surface of the substrate with its longitudinal direction Y extending perpendicular to the X direction of travel of the substrate, i.e. along the width of the substrate, extending over this entire width.

[0290] The position of the laser line focal plane is adjusted to be within the thickness of the functional coating when the substrate is positioned on the conveyor. The power flux density of the laser line at the focal plane is less than 100kW / cm2. The substrate was moved under the laser line at a speed of approximately 8 m / min.

[0291] The functional coating may therefore have been subjected to rapid thermal annealing in which each point of the stack is brought to a temperature of at least 300°C while maintaining a temperature less than or equal to 150°C at any point on the face of the substrate opposite that on which the stack is located.

[0292] It is also possible to combine heat treatments. For example, rapid thermal annealing followed by tempering can be performed. The functional coating and the substrate may have undergone a heat treatment at a high temperature above 500°C, such as tempering, annealing, or bending. The substrate coated with the functional coating may be curved or tempered glass.

[0293] The transparent organic substrates according to the invention may also be made of polymer, rigid or flexible. Examples of polymers suitable according to the invention include, in particular:

[0294] - polyethylene,

[0295] - polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN);

[0296] - polyacrylates such as polymethyl methacrylate (PMMA);

[0297] - polycarbonates;

[0298] - polyurethanes;

[0299] - polyamides;

[0300] - polyimides;

[0301] - fluorinated polymers such as fluoroesters such as ethylene tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), ethylene chlorotrifluoroethylene (ECTFE), fluorinated ethylene-propylene copolymers (FEP);

[0302] - photocrosslinkable and / or photopolymerizable resins, such as thiolene, polyurethane, urethane-acrylate, polyester-acrylate resins and

[0303] - polythiourethanes.

[0304] The substrate is preferably a sheet of glass or glass-ceramic.

[0305] The substrate is preferably transparent. The substrate is preferably colorless (in which case it is clear or extra-clear glass) or colored, for example blue, gray or bronze. The glass is preferably of the soda-lime-silica type, but it can also be borosilicate or alumino-borosilicate glass.

[0306] According to a preferred embodiment, the substrate is made of glass, in particular soda-lime-silica or polymeric organic material.

[0307] 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 8 mm, or even between 2.8 and 6 mm. The substrate can be flat or curved, or even flexible.

[0308] The invention also relates to a glazing comprising at least one material according to the invention. Depending on the intended applications and in particular depending on the desired properties, these glazings may be in the form of monolithic glazing, multiple glazing, laminated glazing or multiple and laminated glazing. The glazing may comprise at least one material according to the invention and an additional substrate assembled in the form of multiple glazing. Conventionally, the faces of a glazing are designated from the outside of the building and by numbering the faces of the substrates from the outside to the inside of the passenger compartment or the room it equips. This means that the incident sunlight passes through the faces in increasing order of their number.

[0309] The most efficient known selective glazings are generally double glazings comprising a functional coating located on face 2, i.e. on the outermost substrate of the building; on its face facing the interlayer gas layer.

[0310] The materials according to the invention mounted in the form of double glazing with the functional coating positioned on face 2, have a high selectivity, in particular greater than 1.70, greater than 1.75, greater than 1.80, greater than 1.85.

[0311] Double glazing has 4 sides, side 1 is on the outside of the building and therefore constitutes the outer wall of the glazing, side 4 is on the inside of the building and therefore constitutes the inner wall of the glazing, sides 2 and 3 are on the inside of the double glazing. The functional coating according to the invention is on side 2 or side 3.

[0312] Triple glazing has 6 faces, face 1 is on the outside of the building and therefore constitutes the outer wall of the glazing, face 6 is on the inside of the building and therefore constitutes the inner wall of the glazing, faces 2 and 3 and 4 and 5 being on the inside of the double glazing. The functional coating according to the invention can be on face 2, face 3 and / or face 5.

[0313] A laminated glazing unit comprises at least one structure of the first substrate / sheet(s) / second substrate type. The polymeric sheet may in particular be based on polyvinyl butyral PVB, ethylene vinyl acetate EVA, polyethylene terephthalate PET, polyvinyl chloride PVC. The functional coating of thin layers is positioned on at least one of the faces of one of the substrates.

[0314] The invention therefore relates to:

[0315] - multiple glazing of the double glazing type with the functional coating on face 2,

[0316] - multiple glazing of the double glazing type with the functional coating on face 3,

[0317] - multiple glazing of the triple glazing type with functional coating on face 2 and face 5,

[0318] - laminated glazing with functional coating on face 2 or 3. These glazings can be mounted on a building or a vehicle.

[0319] Examples

[0320] In all tables showing optical characteristics and performances, the following designations are used:

[0321] DGU: the characteristics are measured in double glazing with a 6 / 12 / 4 structure: 6 mm glass / 12 mm interlayer space filled with air / 4 mm glass, the functional stack coating being positioned on face 2 (face 1 of the glazing being the outermost face of the glazing, as usual).

[0322] SGU: The measured characteristics are sometimes in single glazing with the functional coating positioned on face 2, in particular the parameters a*60° and b*60°.

[0323] A color box was defined for exterior reflection and interior reflection for all glazing.

[0324] I. Materials and deposit conditions

[0325] In these examples, the glass substrates are 4 mm clear aluminosilicate glass substrates.

[0326] For TEM characterization, a membrane is deposited between the substrate and the layered element. Characterization with TEM requires an electron-transparent substrate, for example, a 15 nm thick silicon nitride membrane. The deposition of the layered elements is carried out on two substrates simultaneously: on the glass substrate and on the substrate suitable for TEM analyses. The substrate suitable for TEM, whose size is less than 1 cm2 and whose thickness is about 200pm, is stuck on the glass substrate. It is assumed that, given its size and thickness, the deposition of the layered elements is identical on both substrates.

[0327] Continuous functional metal layers (F) are silver (Ag) layers. For discontinuous silver layers, equivalent thicknesses are considered.

[0328] The blocking layers are metal layers made of nickel and chromium alloy (NiCr). The dielectric coatings of functional coatings include barrier layers and stabilizing layers as dielectric layers. The dielectric layers are selected from:

[0329] - layers based on titanium oxide (TiOx, n = 2.4),

[0330] - layers based on zinc and tin oxide (SnZnO, n = 2.0),

[0331] - layers based on zinc oxide (ZnO, n = 2.0).

[0332] - layers based on silicon nitride (SiaN4, n = 2.0),

[0333] - layers based on silicon oxide (SiC>2, n = 1.5),

[0334] - layers of silicon oxynitride (SiON).

[0335] The conditions for deposition of the layers by sputtering (so-called “magnetron cathode sputtering”) are summarized in Table 1.

[0336] The conditions for depositing the layers, which were deposited by spraying

[0337] (so-called “magnetron cathode sputtering”), are summarized in Table 2.

[0338] At. = atomic; Pds: Weight. II. Glazing with heat-treated materials

[0339] The following tables list the materials and physical thicknesses in nanometers (unless otherwise indicated) of each layer or coating that constitutes the coatings according to their position relative to the substrate carrying the coating (last line at the bottom of the table).

[0340]

[0341] *ECA: Absorbent layered element

[0342] Thickness in nm, *: Equivalent thickness

[0343] The coated substrates undergo a quenching type heat treatment.

[0344]

[0345] Figure 1 represents the selectivity as a function of the values ​​of a*T. In this figure:

[0346] - the point curve represents the examples Cp.1, Cp.2, Cp.3, Cp.4,

[0347] - the square curve represents the examples lnv.1, lnv.2. The level of color in transmission, and more particularly the search for neutrality in transmission (a*T close to 0), regulates the selectivity of bi-Ag coatings.

[0348] It is observed that with an absorbing layer based on NiCr placed in the second dielectric coating, the improvement in neutrality with a*T values ​​going from a value of a*T of -3.4 to -2.5 can only be at the expense of selectivity which goes from 1.73 to 1.65 (A = 0.08).

[0349] The absorbing layered element allows the improvement of neutrality with values ​​of a*T passing from level 2 (a* [-4,-2]) to level 1 (a* [-2,-0]), and this without harming the selectivity which remains above 1.70. III. Second test series

[0350]

[0351] CB: Blocking layer; CF: Functional layer; RD: Dielectric coating. Only the glazing of the invention makes it possible to obtain both effective neutralization with an a*T value lower than -2.2 and high selectivity, notably greater than 1.8.

[0352] IV. Absorbent layered elements

[0353] The table below lists the materials and physical thicknesses in nanometers (unless otherwise indicated) of each layer or coating that makes up the layered element according to their position relative to the substrate carrying the stack (last line at the bottom of the table).

[0354] EC: Layered element, CD: Dielectric layer, dise.: Discontinuous, CB: Metallic blocking layer, *: Equivalent thickness.

[0355] These materials can be used:

[0356] - as is, i.e. without undergoing additional heat treatment at high temperature (hereinafter Ann.),

[0357] - following heat treatment at a high temperature, hereinafter heat-treated material, carried out in a NABER furnace at a temperature of 650°C for 10 minutes (hereinafter TT).

[0358] 1. Optical characterization

[0359] The specific optical absorption characteristics of heat-treated absorbing elements are determined from their absorption spectra. For this, the absorption of the substrate coated with the layered element is calculated. Then, the absorption of the substrate is subtracted.

[0360] We determine:

[0361] - the position of the maximum of the absorption peak (c),

[0362] - its maximum absorption (max),

[0363] - its width at mid-height (W),

[0364] - light absorption in the visible (AL),

[0365] - the colors (a*abs, b*abs) and

[0366] - the neutralization factor Fn (AL xa*abs). The table below shows the results obtained for the elements in layers lnv.1 and lnv.2 and comparative ones.

[0367] According to the invention, a good green-absorbing coating is considered to have the following characteristics, preferably in combination:

[0368] - a peak centered between 490 and 550 nm, preferably around 515,

[0369] - a maximum absorption of less than 20%,

[0370] - a low half-height width because if the width is too large, the a* can no longer be very negative,

[0371] - absorption in the visible less than 16%,

[0372] - a*abs as negative as possible, preferably less than -5, -6, -7, -8, -9, or even -10, and

[0373] - a b* less than +10.

[0374] With heat treatment, a*abs less than -10 are easily obtained.

[0375] The comparative example Cp.T does not show a peak centered between 490 and 550.

[0376] Comparative examples Cp.2' and Cp.4' have too strong an absorption. Therefore, they will have a very negative impact in terms of selectivity if they are used to modify the color of a functional coating.

[0377] Example Cp.3' is suitable but less satisfactory than the materials of the invention lnv.1 and lnv.2'.

[0378] The a*abs. values ​​are not negative enough. The neutralization factor is too low. The cp.6' material comprising a layered element comprising the sequence SiC>2 / Ag dise. / SiC>2 is not absorbent. It would appear that the high oxygen content generates defects in the discontinuous silver layer, which then loses its plasmonic absorption function.

[0379] These examples highlight that the following configurations of the prior art are less advantageous than that of the invention:

[0380] - TiOx dielectric layer / Discontinuous silver layer / TiOx dielectric layer,

[0381] - SnZnO dielectric layer / Discontinuous silver layer / Metallic NiCr layer / ZnO dielectric layer,

[0382] - SnZnO dielectric layer / Discontinuous silver layer / Metallic Ti layer / SnZnO dielectric layer,

[0383] - SnZnO dielectric layer / Discontinuous silver layer / ZnO dielectric layer, - SiN dielectric layer / Discontinuous silver layer / SiN dielectric layer,

[0384] - SiO dielectric layer / Discontinuous silver layer / SiO dielectric layer.

[0385] 2. Characterization of the layers by TEM

[0386] 1. Image processing

[0387] The image analysis process is summarized in Figure 2.

[0388] The original image (Figure 2-a) is denoised with the “denoise_tv_bregman” filter from the “skimage” python library (Figure 2-b). This filter reduces the total intensity variation of the image. Then, to separate the particles from the background, an intensity threshold level is determined by the Otsu method. The Otsu method calculates the histogram of the image intensity and determines the optimal threshold that separates this histogram into two populations with minimal intra-population variance. Pixels below this intensity threshold belong to the image background (in black) and pixels above this threshold belong to the particles (in white). The resulting image is a binarized black and white image (Figure 2-c). A color is added to separate the truncated particles at the edge of the image. These count for the filling calculation but not for the size estimation (Figure 2-d).

[0389] The “regionprops” function (“skimage” library) extracts shape and position data for each object: area, center, major and minor axes, orientation (Figure 2-e).

[0390] 2. Characterization

[0391] The examples according to the invention have the characteristics summarized in the table below.

Claims

Claims 1. Material comprising a transparent substrate coated with a functional coating comprising successively from the substrate an alternation of two continuous silver-based functional metal layers called, starting from the substrate, first and second functional layers, and three dielectric coatings called, starting from the substrate, Di1, Di2 and Di3, each dielectric coating comprising at least one dielectric layer, so that each continuous functional metal layer is arranged between two dielectric coatings, the dielectric coating Di1 and / or the dielectric coating Di2 comprises a layered element comprising: - a first layer comprising silicon chosen from a layer of nitride, oxide or oxynitride, - a discontinuous silver-based layer deposited directly on the first silicon-based layer comprising nanometric silver particles, - a second layer comprising silicon chosen from a layer of nitride, oxide or oxynitride deposited directly on the discontinuous silver-based layer.

2. Material according to the preceding claim, characterized in that: - the first or second layer comprising silicon comprises oxygen, and - the first or second layer comprising silicon comprises nitrogen.

3. Material according to any one of the preceding claims, characterized in that: the second layer comprising silicon is a layer of silicon oxynitride and / or the first layer comprising silicon is a layer of silicon oxynitride, and / or - the first and second layers comprising silicon both comprise oxygen and in that the first layer comprising silicon comprises a greater proportion of oxygen than the second layer comprising silicon.

4. Material according to any one of the preceding claims, characterized in that the first layer comprising silicon has a thickness of between 2 and 20 nm and / or the second layer comprising silicon has a thickness of between 2 and 20 nm.

5. Material according to any one of the preceding claims, characterized in that the discontinuous silver-based layer has an equivalent thickness of less than 4.0 nm, or even less than 3.0 nm or less than 2.0 nm.

6. Material according to any one of the preceding claims, characterized in that the layered element has an absorption peak in the visible range having a maximum between 490 and 550 nm.

7. Material according to any one of the preceding claims, characterized in that the layered element comprises an absorption peak in the visible range whose width at half-height is less than 350 nm.

8. Material according to any one of the preceding claims, characterized in that the layered element has a light absorption in the visible range of between 8 and 20%, absorption measured on the layered element side on a 4 mm thick clear glass substrate.

9. Material according to any one of the preceding claims, characterized in that each dielectric coating located below a functional layer comprises a zinc oxide-based layer located below, in contact with or separated by a blocking layer, the functional layer and having a thickness greater than or equal to 3 nm.

10. Material according to any one of the preceding claims, characterized in that each dielectric coating located above a functional layer comprises a zinc oxide-based layer located above, in contact with or separated by a blocking layer, the functional layer.

11. Material according to any one of the preceding claims, characterized in that: - the first functional layer has a thickness between 7 and 20 nm, and / or - the second functional layer has a thickness between 7 and 20 nm.

12. Material according to any one of the preceding claims, characterized in that: - the first dielectric coating Di 1 has an optical thickness between 60 and 120 nm, - the second dielectric coating Di2 has an optical thickness between 120 and 250 nm, - the third dielectric coating Di3 has an optical thickness between 40 and 120 nm.

13. Material according to any one of the preceding claims, characterized in that the substrate is made of glass, in particular soda-lime-silica or polymeric organic material.

14. Material according to any one of the preceding claims, characterized in that the surface filling of the nanometric silver particles is between 10 and 60%, between 10 and 50%, preferably between 20 and 40%.

15. Material according to any one of the preceding claims, characterized in that the nanometric silver particles have: - a median equivalent diameter between 1 and 10 nm, preferably between 2 and 8 nm, and / or - an average interparticle distance is between 3 and 10 nm, preferably between 4 and 8 nm.

16. Glazing comprising at least one material according to one of claims 1 to 15 and an additional substrate assembled in the form of multiple glazing.

Images