BR112014016069B1 - ARTICLE COMPRISING A SUBSTRATE PRESENTING AT LEAST ONE MAIN SURFACE COATED WITH A MULTILAYER INTERFERENTIAL COATING, AND, PROCESS OF MANUFACTURING AN ARTICLE - Google Patents

Abstract

ARTICLE COATED WITH AN INTERFERENTIAL COATING PRESENTING STABLE PROPERTIES OVER TIME. The present invention relates to an article comprising a substrate having at least one main surface coated with a multilayer interferential coating, wherein said coating comprises a layer A having a refractive index less than or equal to 1.55, characterized by the fact that : - said layer A constitutes: either the outer layer of the interferential coating, or an intermediate layer, which is directly in contact with the outer layer of the interferential coating, wherein said outer layer of the interferential coating is a layer B having a refractive index lower than or equal to 1.55, - said layer A having been obtained by deposition, by ion beam, of activated species obtained from at least one compound C, in gaseous form, containing in the respective structure at least at least one silicon atom, at least one carbon atom, at least one hydrogen atom and, optionally, at least one nitrogen atom and/or at least one oxygen atom, wherein the deposition of said layer A is carried out on the presence of nitrogen and/or oxygen when compound A does not contain (...).

Description

[0001] The present invention generally relates to an article, preferably an optical article, particularly an ophthalmic lens, having an interferential coating, preferably an anti-reflective coating, whose optical properties are stable over time and which in addition Furthermore, it has improved thermomechanical properties, as well as a process for preparing an article of said nature.

[0002] It is known to treat ophthalmic lenses, whether mineral or organic, in order to prevent the formation of parasitic reflections that are bothersome to the lens user and their interlocutors. The lens is then provided with a single- or multi-layer anti-reflective coating, generally made of mineral material.

[0003] During the preparation of an anti-reflective coating, target performances are generally chosen, which are the effectiveness of the anti-reflective coating defined by the reflection coefficients Rm and Rv and the respective residual reflection color, essentially characterized by the tone angle h and chroma C*. These last two parameters guarantee the aesthetic side of the anti-reflective treatment for the user and their surroundings.

[0004] Now, the optical properties of the anti-reflective coating layers and, more generally, the optical properties of the interferential coating layers, particularly those of the silicon layers, evolve over time, although their effectiveness characteristics and above all aesthetics may differ between the moment the coating is formed on the article and the moment it is sold, when the glass has been kept in stock, and/or during the use of the article by the user, after the sale.

[0005] One way to solve the first problem is to estimate the evolution over time of the anti-reflective coating and to produce an anti-reflective coating different from that desired but which will evolve over time in order to reach the target values. , during storage.

[0006] However, considering that evolution over time is empirical and not always modelable, the problem of selling lenses treated with anti-reflective coatings presenting the target performances persists.

[0007] On the other hand, in the case of prescription lenses, sold to the user in the days following their manufacture, the problem of modification of optical properties during use by the user remains unresolved.

[0008] Therefore, it is desirable to design new interferential coatings, particularly anti-reflective, less sensitive to the evolution over time of their optical properties, while significantly preserving or improving the other properties of the interferential coating, such as mechanical properties, adhesion .

[0009] According to the present invention, the problem is solved by depositing as an external layer of the interferential coating a low refractive index layer formed by ion beam deposition, of a layer obtained exclusively from precursor materials of an organic nature and in gaseous form.

[0010] US patent 6,919,134 describes an optical article comprising an anti-reflective coating comprising at least one so-called “hybrid” layer obtained by co-evaporation of an organic compound and an inorganic compound, which gives it better adhesion, a better thermal resistance and better abrasion resistance. The anti-reflective coating preferably comprises two “hybrid” layers in internal and external position. These layers are generally deposited by ionic-assisted co-evaporation typically of silicon and a modified silicone oil.

[0011] Application JP 2007-078780 describes a spectacle lens comprising a multilayer anti-reflective coating, the outer layer of which is a low refractive index layer called “organic”. This layer is deposited by liquid means (by centrifugation or dip coating), while the inorganic layers of the anti-reflective coating are deposited by vacuum deposition with ion assistance. The patent application indicates that such an anti-reflective stack has better thermal resistance than an anti-reflective coating composed exclusively of inorganic layers. Said "organic" layer preferably comprises a mixture of silicon particles and an organosilane binding agent such as Y-glycidoxypropyltrimethoxysilane.

[0012] Application JP 05-323103 describes the incorporation of a fluorinated organic compound in the last layer of a multilayer optical stack, comprising layers of SiO2 and TiO2, with a view to making it hydrophobic and therefore minimizing the modification of its characteristics optics caused by water absorption. The fluorinated layer is obtained by vapor deposition of the layer's constituent material in an atmosphere composed of the fluorinated precursor, which can be tetrafluoroethylene or a fluoroalkyl silane.

[0013] The main objective of the present invention is the preparation of interferential coatings, particularly anti-reflection, whose optical properties, particularly chroma (considering that users are more sensitive to this parameter), are more stable over time than known interferential coatings. Such interferential coatings would possess the target characteristics from the end of the deposition of the different layers of the overlay, which would guarantee their performance and simplify quality control. This technical issue is not addressed in the aforementioned patents or patent application.

[0014] On the other hand, during the cutting and assembly of a lens in the optics, the lens undergoes mechanical deformations that can cause cracks in the mineral interferential coatings, particularly when the operation is not carried out carefully. Similarly, temperature stresses (assembly heating) can cause cracks in the interferential coating. Depending on the number and size of the cracks, they can disturb the user's eyes and prevent the lens from being sold.

[0015] Thus, another objective of the present invention is to obtain interferential coatings presenting improved thermomechanical properties, while maintaining good adhesion properties. The present invention is particularly aimed at articles having an improved critical temperature, that is, presenting good resistance to cracking when subjected to an increase in temperature.

[0016] Another objective of the present invention is to provide a process for manufacturing a simple, easy to perform and reproducible interferential coating.

[0017] The inventors discovered that a modification of the nature of the outer layer of the interferential coating, which is generally a low refractive index layer, typically a silicon layer, allowed achieving the proposed objectives. According to the present invention, this layer is formed by ion beam deposition of activated species, in gaseous form, obtained exclusively from precursor materials of an organic nature.

[0018] Therefore, the objectives proposed according to the present invention are achieved through an article comprising a substrate having at least one main surface coated with a multilayer interferential coating, wherein said coating comprises a layer A having an index of refraction less than or equal to 1.55, which constitutes: a. either the outer layer of the interferential coating, b. or an intermediate layer, which is directly in contact with the outer layer of the interferential coating, wherein said outer layer of the interferential coating in this second case is a layer B having a refractive index less than or equal to 1.55, and, said layer A was obtained by deposition, by ion beam, of activated species from at least one compound C, in gaseous form containing in the respective structure at least one silicon atom, at least one carbon atom, at least a hydrogen atom and, optionally, at least one nitrogen atom and/or at least one oxygen atom, wherein the deposition of said layer A is carried out in the presence of nitrogen and/or oxygen when compound C does not contain nitrogen and/or oxygen, and; said layer A was not formed from inorganic precursor compounds.

[0019] The present invention also refers to a process for manufacturing an article of said nature, comprising at least the following steps:

[0020] - providing an article comprising a substrate having at least one main surface;

[0021] - depositing on said main surface of the substrate a multilayer interferential coating, wherein said coating comprises a layer A having a refractive index less than or equal to 1.55, which constitutes: i. - either the outer layer of the interferential coating, ii. - either an intermediate layer, which is directly in contact with the outer layer of the interferential coating, wherein said outer layer of the interferential coating is a B layer having a refractive index less than or equal to 1.55,

[0022] - recover an article comprising a substrate having a main surface coated by said interferential coating comprising said layer A, wherein said layer A was obtained by deposition, with an ion beam, of activated species from at least a compound C, in gaseous form, containing in its respective structure at least one silicon atom, at least one carbon atom, at least one hydrogen atom and, optionally, at least one nitrogen atom and/or at least one atom of oxygen, in which the deposition of said layer A is carried out in the presence of nitrogen and/or oxygen when compound C does not contain nitrogen and/or oxygen, and said layer A is not formed from inorganic precursor compounds.

[0023] Next, the present invention will be described in more detail with reference to the attached figure, in which figure 1 is a schematic representation of the deformation suffered by the lens and the way in which this deformation D is measured during the bending resistance test described. in the experimental part.

[0024] According to the present application, when an article comprises one or more coatings on its surface, the expression “depositing a layer or a coating on the article” means that a layer or a coating is deposited on the uncovered surface ( exposed) of the external coating of the article, meaning the coating furthest from the substrate.

[0025] A coating that is “on” a substrate or that has been deposited “on” a substrate is defined as a coating that (i) is positioned on top of the substrate, (ii) is not necessarily in contact with the substrate, either to say that one or more intermediate coatings may be arranged between the substrate and the coating in question and (iii) it does not necessarily completely cover the substrate (although it preferably covers it). When “a layer 1 is located under a layer 2” it is evident that layer 2 is further away from the substrate than layer 1.

[0026] The article prepared according to the present invention comprises a substrate, preferably transparent, having front and rear main faces, wherein at least one of said main faces comprises an interferential coating, preferably the two main faces.

[0027] The rear face (generally concave) of the substrate means the face that, during use of the article, is closest to the user's eye. Conversely, the front (generally convex) face of the substrate means the face that, during use of the article, is furthest from the user's eye.

[0028] Although the article according to the present invention can be any article, such as a screen, a glazing, protective glasses usable in particular in work environments, or a mirror, preferably it is an optical article, particularly an optical lens, particularly preferably an ophthalmic lens, for spectacles, or an outline of an optical or ophthalmic lens such as a semi-finished optical lens, particularly a lens for spectacles. The lens can be a polarized lens, a colored lens, or a photochromic lens. Preferably, the ophthalmic lens according to the present invention has a high transmission.

[0029] The interferential coating according to the present invention can be formed on at least one of the main faces of a bare substrate, that is to say uncoated, or on at least one of the main faces of a substrate already coated with one or more coatings functional.

[0030] The substrate of the article according to the present invention is preferably an organic lens, for example made of thermoplastic or thermosetting plastic material. This substrate can be chosen from among the substrates cited in application WO 2008/062142, for example a substrate obtained by (co)polymerization of diethylene glycol bis allyl carbonate, a substrate in poly(thio)urethane or a substrate in bis polycarbonate. (phenol A) (thermoplastic) PC.

[0031] Before deposition of the interferential coating on the substrate eventually coated, for example with an anti-abrasion and/or anti-scratch coating, it is common to subject the surface of said substrate to a physical or chemical activation treatment, intended to increase the adhesion of the interferential coating. This pretreatment is generally conducted under vacuum. This can be a bombardment with energetic and/or reactive species, for example an ion beam (“Ion Pre-Cleaning” or “IPC”) or an electron beam, a treatment by corona discharge, by shattering, by a UV treatment, or a vacuum plasma treatment, usually an oxygen or argon plasma. It may also involve an acidic or basic surface treatment and/or solvent agents (water or organic solvent agent). Several of these treatments can be combined. Thanks to these cleaning treatments, the cleanliness and reactivity of the substrate surface are optimized.

[0032] By energetic (and/or reactive) species, we particularly mean ionic species having an energy in the range of 1 eV to 300 eV, preferably from 1 eV to 150 eV, particularly from 10 eV to 150 eV, particularly preferably from 40 eV to 150 eV. Energetic species can be chemical species such as ions, radicals or species such as photons or electrons.

[0033] The preferred pre-treatment of the substrate surface is an ion bombardment treatment, carried out using an ion gun, in which the ions are particles made up of gas atoms from which one or more electrons are extracted. Preferably as ionized gas, argon (Ar+ ions) is used, but also oxygen, or mixtures thereof, under an acceleration voltage generally in the range of 50 V to 200 V, a current density generally in the range of 10 μA/cm2e 100 μA/cm2 on the activated surface and generally under a residual pressure in the vacuum chamber that can vary between 8.10-5 mbar and 2.10-4 mbar.

[0034] The article according to the present invention comprises an interferential coating, preferably formed on an anti-abrasion coating. Preferred anti-abrasion coatings are coatings based on epoxysilane hydrolysates having at least two hydrolysable groups, preferably at least three linked to the silicon atom.

[0035] The preferred hydrolyzable groups are alkoxysilane groups.

[0036] The interferential coating can be any interferential coating classically used in the field of optics, particularly ophthalmic optics, except when it includes a layer A formed by deposition, by ion beam, of activated species obtained from an organic silicon derivative , in gaseous form. The interferential coating may be, without limitation, an anti-reflective coating, a reflective (mirror) coating, an infrared filter or an ultraviolet filter, preferably an anti-reflective coating.

[0037] An anti-reflective coating is defined as a coating, deposited on the surface of an article, that improves the anti-reflective properties of the final article. It allows reducing the reflection of light at the article-air interface over a relatively wide portion of the visible spectrum.

[0038] As is well known, interferential coatings, preferably anti-reflective coatings, classically comprise a monolayer or multilayer stack of dielectric materials. Preferably they are multilayer coatings, comprising layers of high refractive index (HI) and layers of low refractive index (BI).

[0039] In the present application, a layer of the interferential coating is said high refractive index layer when the respective refractive index is greater than 1.55, preferably greater than or equal to 1.6, particularly greater than or equal to 1, 8, particularly preferably greater than or equal to 2.0. A layer of the interferential coating is said low refractive index layer when the respective refractive index is less than or equal to 1.55, preferably less than or equal to 1.50, particularly less than or equal to 1.45. Unless otherwise indicated, the refractive indices referred to in the present invention are expressed at 25°C for a wavelength of 630 nm.

[0040] HI layers are classic high refractive index layers, well known in the art. They generally comprise one or more mineral oxides such as, without limitation, zirconia (ZrO2), titanium oxide (TiO2), tantalum pentoxide (Ta2O5), neodymium oxide (Nd2O5), hafnium oxide (HfO2) , praseodymium oxide (Pr2O3), preseodymium titanate (PrTiO3), La2O3, Nb2O5, Y2O3, indium oxide In2O3, or tin oxide SnO2. Preferred materials are TiO2, Ta2O5, PrTiO3, ZrO2, SnO2, In2O3 and mixtures thereof.

[0041] BI layers are also well known in the art and may comprise, without limitation, SiO2, MgF2, ZrF4, aluminum (Al2O3) in a small proportion, AlF3, and their respective mixtures, preferably SiO2. SiOF (fluoro-doped SiO2) layers can also be used. Ideally, the interferential coating of the present invention does not comprise any layer comprising a mixture of silicon and aluminum.

[0042] Generally, HI layers have a physical thickness that varies in the range of 10 nm to 120 nm and BI layers have a physical thickness that varies in the range of 10 nm to 100 nm.

[0043] Preferably, the total thickness of the interferential coating is less than 1 micrometer, particularly less than or equal to 800 nm, more particularly less than or equal to 500 nm. The total thickness of the interferential coating is generally greater than 100 nm, preferably greater than 150 nm.

[0044] Preferably, the interferential coating, which is preferably an anti-reflective coating, comprises at least two layers of low refractive index (BI) and at least two layers of high refractive index (HI). Preferably, the total number of layers of the interferential coating is less than or equal to 8, particularly less than or equal to 6.

[0045] It is not necessary for the HI and BI layers to be alternated in the interferential coating, although they may be so in accordance with an embodiment of the present invention. Two HI layers (or more) can be deposited on top of each other, just as two BI layers (or more) can be deposited on top of each other.

[0046] According to an embodiment of the present invention, the interferential coating comprises a sub-layer. In this case this generally constitutes the first layer of said interferential coating in the order of deposition of the layers, that is to say the layer of the interferential coating that is in contact with the underlying coating (which is generally an anti-abrasion and/or anti-scratch coating). or with the substrate, when the interferential coating is deposited directly on the substrate.

[0047] By sub-layer of the interferential coating, we mean a coating with a relatively significant thickness, used for the purpose of improving the abrasion and/or scratch resistance of said coating and/or promoting its adhesion to the substrate or the underlying coating. The sublayer according to the present invention can be chosen from among the sublayers described in WO 2010/109154.

[0048] Preferably, the sub-layer has a thickness in the range of 100 nm to 200 nm. Preferably it is exclusively mineral in nature and preferably consists of silicon SiO2.

[0049] The article according to the present invention can be made antistatic thanks to the incorporation, in the interferential coating, of at least one electrically conductive layer. By “antistatic”, we mean the property of not retaining and/or developing a significant electrostatic charge. An article is generally considered to have acceptable anti-static properties when it does not attract and bind dust and small particles after one of its surfaces has been rubbed with a suitable cloth.

[0050] The electrically conductive layer can be located at different points of the interferential coating, as long as it does not interfere with its anti-reflective properties. It can, for example, be deposited on the sub-layer of the interferential coating, when this exists. Preferably it is located between two dielectric layers of the interferential coating and/or under a low refractive index layer of the interferential coating.

[0051] The electrically conductive layer must be thin enough not to alter the transparency of the interferential coating. Generally, their thickness varies in the range of 0.1 nm to 150 nm, particularly from 0.1 nm to 50 nm, depending on their nature. A thickness less than 0.1 nm generally does not allow sufficient electrical conductivity to be obtained, while a thickness greater than 150 nm generally does not allow the necessary transparency and low absorption characteristics to be obtained.

[0052] The electrically conductive layer is preferably manufactured from an electrically conductive and highly transparent material. In this case, the respective thickness preferably varies in the range of 0.1 nm to 30 nm, particularly from 1 nm to 20 nm and particularly preferably from 2 nm to 15 nm. The electrically conductive layer preferably comprises a metallic oxide chosen from indium, tin, zinc oxides and mixtures thereof. Indium tin oxide (In2O3:Sn, tin-doped indium oxide) and indium oxide (In2O3) as well as tin oxide SnO2 are preferred. According to an optimal embodiment, the electrically conductive and optically transparent layer is an indium tin oxide layer, called an ITO layer.

[0053] Generally, the electrically conductive layer contributes to obtaining anti-reflective properties and constitutes a high refractive index layer in the interferential coating. This is the case with layers manufactured from an electrically conductive and highly transparent material such as ITO layers.

[0054] The electrically conductive layer can also be a layer of a noble metal (Ag, Au, Pt, etc.) of very thin thickness, typically less than 1 nm thick, particularly less than 0.5 nm.

[0055] The different layers of the interferential coating (of which the optional antistatic layer is a part) except layer A are preferably deposited by vacuum deposition according to any of the following techniques: i) by evaporation, optionally assisted by an ion beam ; ii) by ion beam spraying; iii) by sputtering; iv) by plasma-assisted chemical vapor deposition. These different techniques are described in the works “Thin Film Processes” and “Thin Film Processes II”, Vossen & Kern, Ed., Academic Press, 1978 and 1991 respectively. A particularly recommended technique is the vacuum evaporation technique.

[0056] Preferably, the deposition of each layer of the interferential coating is carried out by evaporation under vacuum.

[0057] Layers A and B of the interferential coating (layer B being optional) will be described below. They are low refractive index layers in the sense of the present invention, considering that the respective refractive index is < 1.55. Preferably, according to embodiments of the present invention, the refractive index of layer A is greater than or equal to 1.45, particularly greater than 1.47, particularly preferably greater than or equal to 1.48, and ideally greater than or equal to at 1.49.

[0058] The deposition of layer A is obtained by deposition, by ion beam, of activated species obtained from at least one compound C, in gaseous form, containing in the respective structure at least one silicon atom, at least one carbon atom, at least one hydrogen atom and, optionally, at least one nitrogen atom and/or at least one oxygen atom, wherein the deposition of said layer A is carried out in the presence of nitrogen and/or oxygen when compound C does not contain nitrogen and/or oxygen.

[0059] Preferably, the deposition is carried out in a vacuum container, containing an ion gun directed towards the substrates to be coated, which emits a beam of positive ions generated in a plasma within the ion gun towards them. Preferably, the ions that come out of the cannon are particles made up of gas atoms from which one or more electron(s) are extracted and formed from a rare gas, oxygen or a mixture of two or more of these gases.

[0060] A gaseous precursor, compound C is introduced into the container under vacuum, preferably in the direction of the ion beam and is activated under the effect of the ion gun.

[0061] Without wanting to be limited by any theory, the inventors think that the plasma from the ion gun is projected into a zone located at a certain distance before the gun, without, however, reaching the substrates to be coated and that an activation/ Dissociation of the precursor compound C preferably takes place in this zone and generally in the vicinity of the ion gun and to a lesser extent within the ion gun.

[0062] This deposition technique using an ion gun and a gaseous precursor, sometimes called “ion beam deposition” is particularly described in patent US5508368.

[0063] According to the present invention, preferably, the only point in the container where a plasma is generated is the ion gun.

[0064] The ions can be subjected, if necessary, to neutralization before exiting the ion gun. In this case, the bombardment will always be considered as ionic. Ionic bombardment causes atomic reorganization and densification in the layer in progress, which allows it to be applied while it is being formed.

[0065] During the process according to the present invention, the surface to be treated is preferably bombarded by ions, with a current density generally in the range of 20 μA/cm2 to 1000 μA/cm2, preferably 30 μA/cm2 to 500 μA/cm2, particularly from 30 μA/cm2 to 200 μA/cm2 on the activated surface and generally with a residual pressure in the vacuum vessel that varies in the range of 6.10-5 mbar to 2.10-4 mbar, preferably from 8.10-5 mbar to 2.10 -4 mbar. Preferably an argon and/or oxygen ion beam is used. When a mixture of argon and oxygen is used, the Ar/O2 molar ratio is preferably < 1, particularly < 0.75 and particularly preferably < 0.5. This ratio can be controlled by adjusting the gas flow rates in the ion gun. The argon flow preferably varies in the range of 0 sccm to 30 sccm. The O2 oxygen flow preferably varies in the range of 5 sccm to 30 sccm and is greater the higher the A layer precursor compound flow.

[0066] The ions of the ion beam, preferably coming from an ion gun used during the deposition of layer A, preferably have an energy in the range of 75 eV to 150 eV, preferably from 80 eV to 140 eV, particularly from 90 eV to 110 eV.

[0067] The activated species formed are typically radicals or ions.

[0068] According to the technique of the present invention, this is distinguished from deposition by means of a plasma (for example by PECVD) in that it involves bombardment by means of a beam of ions of layer A in the course of formation, preferably emitted by an ion gun.

[0069] In addition to ion bombardment during deposition, it is possible to carry out plasma treatment concomitantly or not with ion beam deposition of layer A.

[0070] Preferably, the layer deposition is carried out without assistance by a plasma at the level of the substrates.

[0071] In addition to layer A, other layers of the ion beam interferential coating can also be deposited.

[0072] The evaporation of layer A precursor materials, conducted under vacuum, can be carried out using a Joule effect thermal source.

[0073] The precursor material of layer A comprises at least one compound C, which is organic in nature, containing in its respective structure at least one silicon atom and at least one carbon atom, at least one hydrogen atom and, optionally, at least one nitrogen atom and/or at least one oxygen atom.

[0074] Preferably, compound C comprises at least one nitrogen atom and/or at least one oxygen atom, preferably at least one oxygen atom.

[0075] The concentration of each chemical element in layer A (Si, O, C, H) can be determined using the RBS (Rutherford Backscattering Spectrometry) and ERDA (Elastic Recoil Detection Analysis) technique.

[0076] The atomic percentage of carbon atoms in layer A preferably varies in the range of 10% to 25%, particularly 15% to 25%. The atomic percentage of hydrogen atoms in layer A preferably varies in the range of 10% to 40%, particularly 10% to 20%. The atomic percentage in silicon atoms in layer A preferably varies in the range of 5% to 30%, particularly 15% to 25%. The atomic percentage in oxygen atoms preferably varies in the range of 20% to 60%, particularly 35% to 45%.

[0077] Non-limiting examples of organic precursor compounds of layer A, cyclic or non-cyclic, are the following compounds: octamethylcyclotetrasiloxane (OMCTS), decamethylcyclopentassiloxane, dodecamethylcyclohexasiloxane, hexamethylcyclotrisiloxane, hexamethyldisiloxane (HMDSO), octamethyltrisiloxane, decamethyltetrasiloxane, tetraethoxysilane, vinyltrimethylsilane, hexamethyldisilazane, hexamethyldisilane, hexamethylcyclotrisilazane, vivilmethyldiethoxysilane, divinyltetramethyldisiloxane, tetramethyldisiloxane, a tetraalkylsilane such as tetramethylsilane.

[0078] Preferably, the precursor compound of layer A comprises at least one silicon atom carrying at least one alkyl group, preferably at C1-C4, particularly two identical or different alkyl groups, preferably at C1-C4, for example the group methyl.

[0079] Preferred layer A precursor compounds comprise a Si-O-Si group, particularly a group:

[0080]

[0081] wherein R1 to R4 independently designate alkyl groups, preferably at C1-C4, for example the methyl group.

[0082] Preferably, the silicon atom(s) of the precursor compound of layer A do not contain any hydrolyzable group. Non-limiting examples of hydrolyzable groups are chloro, bromine, alkoxy, acyloxy groups. Groups comprising a Si-O-Si chain are not considered to be “hydrolyzable groups” within the meaning of the present invention.

[0083] The silicon atom(s) of the precursor compound of layer A are preferably uniquely linked to alkyl groups and/or to groups comprising a -O-Si or -NH-Si chain in order to form a Si-O-Si group or Si-NH-Si.

[0084] The preferred layer A precursor compounds are OMCTS and HMDSO. The precursor compound of layer A is preferably introduced into the vacuum container in which the articles according to the present invention are prepared in gaseous form, controlling the respective flow rate. This means that it is preferably not vaporized inside the container under vacuum. The A-layer precursor compound feed is located at a distance from the ion gun outlet that varies in the range of 30 cm to 50 cm.

[0085] Preferably, layer A does not comprise any fluorinated compound. According to the present invention, it is not formed from inorganic precursor compounds (minerals), particularly, it is not formed from metal oxide precursors. This is particularly distinguished from the “hybrid” layers described in US application 6,919,134. Preferably, layer A does not contain any distinct metal oxide phase, particularly it does not contain inorganic compounds. In the present application, metalloid oxides are considered to be metal oxides.

[0086] The process that allows the formation of the interferential coating according to the present invention is much simpler and less expensive than the co-evaporation processes of an organic compound and an inorganic compound, as for example the one described in the US application 6,919,134. In practice, co-evaporation processes are very difficult to carry out and difficult to control due to reproducibility problems. The amounts of organic and inorganic compounds present in the deposited layer vary greatly from one embodiment to another.

[0087] Layer A, being formed by vacuum deposition, does not comprise silane hydrolyzate and is distinguished from sol-gel coatings obtained by liquid means.

[0088] Said layer A constitutes either the outer layer of the interferential coating, that is to say the layer of the interferential coating furthest from the substrate in the stacking order, or the layer that is directly in contact with the outer layer of the interferential coating, in that the outer layer of the interferential coating is a B layer having a refractive index less than or equal to 1.55. In this second case, which constitutes the preferred embodiment, layer A constitutes the penultimate layer of the interferential coating in the stacking order.

[0089] Preferably, layer B contains at least 50% by mass of silicon, relative to the total mass of layer B, particularly 75% and particularly preferably 90% or more, ideally 100%. According to a preferred embodiment, layer B constitutes a silicon-based layer. Preferably it is deposited by evaporation under vacuum.

[0090] Layer B is preferably deposited without treatment by activated species, particularly without ionic assistance.

[0091] Layer A preferably has a thickness in the range of 20 nm to 150 nm, particularly 25 nm to 120 nm. When forming the outer layer of the interferential coating, layer A preferably has a thickness in the range of 60 nm to 100 nm. When forming the layer directly in contact with the external layer B of the interferential coating, layer A preferably has a thickness in the range of 20 nm to 100 nm, particularly 25 nm to 90 nm.

[0092] Layer B, when present, preferably has a thickness in the range of 2 nm to 60 nm, particularly 5 nm to 50 nm. Preferably, when layer B is present, the sum of the thicknesses of layers A and B varies in the range of 20 nm to 150 nm, particularly from 25 nm to 120 nm and particularly preferably from 60 nm to 100 nm.

[0093] Preferably, all low refractive index layers of the interferential coating according to the present invention are of inorganic nature with the exception of layer A (that is to say, the other low refractive index layers of the interferential coating preferably do not contain compound organic).

[0094] Preferably, all layers of the interferential coating according to the present invention are of an inorganic nature, with the exception of layer A, which means that layer A preferably constitutes the only layer of an organic nature of the interferential coating according to present invention (the other layers of the interferential coating preferably do not contain organic compound).

[0095] Another property to take into account when designing an interferential coating is mechanical stresses. The voltage of layer A is zero or negative. In the latter case, the layer is in compression. This compressive stress preferably varies in the range of 0 MPa to -500 MPa, particularly from -20 MPa to -500 MPa, particularly preferably from -50 MPa to -500 MPa. The optimum compressive stress varies in the range of -150 MPa to -400 MPa and particularly from -200 MPa to -400 MPa. It is measured at a temperature of 20° C and 50% relative humidity as described below. It is the deposition conditions according to the present invention that allow this tension to be achieved.

[0096] The principle of measuring stress is based on following the formation of a thin substrate. Knowing the geometry and mechanical properties of the substrate, the respective deformation and the thickness of the deposited layer, the stresses are calculated with the aid of Stoney's formula. The atot voltage is obtained by measuring the curvature of practically flat polished silicon (100) or mineral glass substrates before and after deposition of a monolayer according to the present invention or of a complete AR stack on a face of the substrate having a concavity very light, calculating the tension value using Stoney's formula:

[0097]

[0098] in which is the biaxial elastic modulus of the substrate, ds is the substrate thickness (m), df is the film thickness (m), Es is the Young's modulus of the substrate (Pa), Vs is the Poisson's ratio of the substrate,

[0099]

[00100] where R1 is the radius of curvature of the substrate measured before deposition, R2 is the radius of curvature of the film-coated substrate measured after deposition.

[00101] The curvature is measured using a Tencor FLX 2900 (Flexus) device. A class IIIa laser of 4 milliwatts (mW) power at 670 nm is used. The device allows the measurement of internal voltages as a function of time or temperature (maximum temperature of 900° C).

[00102] The following parameters are used to calculate voltage:

[00103] Si biaxial elastic modulus: 180 GPa.

[00104] Si substrate thickness: 300 microns.

[00105] Scan length (Scan): 40 mm.

[00106] Thickness of the deposited film (measured by ellipsometry): 200-500 nm.

[00107] Measurements are carried out at ambient air temperature.

[00108] To determine the tension of the interferential coating, the coating is deposited on the same adapted substrate, proceeding in the same way.

[00109] The stress of the interferential coating according to the present invention generally varies in the range of 0 MPa to -400 MPa, preferably from -50 MPa to -300 MPa, particularly from -80 MPa to

[00110] -250 MPa and particularly preferably from -100 MPa to -200 MPa.

[00111] The A layers according to the present invention have elongations at break greater than those of the inorganic layers and therefore can undergo deformation without forming cracks. Therefore, the article according to the present invention has an increased resistance to bending, as demonstrated in the experimental part.

[00112] The critical temperature of a coated article according to the present invention is preferably greater than or equal to 80° C, particularly greater than or equal to 90° C, and particularly preferably greater than or equal to 100° C. This high critical temperature is due to the presence of layer A in the interferential coating, as demonstrated in the experimental part. Without wishing to give a limiting interpretation to the present invention, the inventors think that, in addition to the nature of the layer, the use of layers A, allowing to increase the compression tension of the stacking assembly, improves the critical temperature of the article.

[00113] In the present application, the critical temperature of an article or coating is defined as that from which ruptures appear in the stacking present on the surface of the substrate, which translates into degradation of the interferential coating.

[00114] Thanks to the respective improved thermomechanical properties, the interferential coating according to the present invention can be applied to a single face of a semi-finished lens, generally the respective front face, where the other face of said lens will still be manufactured and treated. The interferential coating on the respective front face is not faded by the increase in temperature generated by the treatments that the back face will undergo during the hardening of the coatings that will be deposited on that back face or any other action likely to increase the temperature of the lens.

[00115] According to a preferred embodiment, the interferential coating according to the present invention, in the order of stacking on the surface of the optionally coated substrate, comprises a layer of ZrO2, generally 10 nm to 40 nm thick and preferably from 15 nm to 35 nm, a layer of SiO2 generally from 10 nm to 40 nm thick and preferably from 15 nm to 35 nm, a layer of ZrO2 or TiO2, generally from 40 nm to 150 nm thick, preferably from 50 nm to 120 nm, an ITO layer, generally 1 nm to 15 nm thick and preferably 2 nm to 10 nm, and optionally an A layer according to the present invention, generally 50 nm to 150 nm thick and preferably 60 nm to 100 nm, a layer A according to the present invention coated with a layer B according to the present invention (in this second case, the sum of the thicknesses of layers A and B generally varies in the range of 50 nm to 150 nm and preferably from 60 nm to 100 nm).

[00116] Preferably, the average reflection factor in the visible domain (400 nm - 700 nm) of an article coated with an interferential coating according to the present invention, designated by Rm, is less than 2.5% per face, particularly less at 2% per side and particularly preferably less than 1% per side of the article. According to an optimal embodiment, the article comprises a substrate whose two main surfaces are coated with an interferential coating according to the present invention and has a total Rm value (reflection accumulation due to both sides) of less than 1% . The means for achieving said Rm values are known to the person skilled in the art.

[00117] The light reflection factor Rv of an interferential coating according to the present invention is less than 2.5% per face, preferably less than 2% per face, particularly preferably less than 1% per face of the article, particularly < 0.75%, particularly preferably <0.5%.

[00118] In the present application, the “average reflection factor” Rm (average of the spectral reflection over the entire visible spectrum between 400 nm and 700 nm) and the luminous reflection factor Rv are those as defined in the ISO 13666:1998 standard and measured in accordance with ISO 8980-4.

[00119] The colorimetric coefficients of the article according to the present invention in the CIE L*a*b* colorimetric system are calculated in the range of 380 nm to 780 nm taking into account the illuminant D 65 and the observer (incidence angle: 10 °). It is possible to prepare interferential coatings without limitation regarding the respective tone angle. However, the tone angle h preferably varies in the range of 120° to 150°, which produces a coating showing a green residual reflection and the chroma C* is preferably less than 15, particularly less than 10.

[00120] The optical properties of the articles according to the present invention are stable over time. Preferably, the respective chroma C* does not vary by more than 1, particularly by more than 0.5 during a period of 3 months after the respective preparation, that is to say at the time of the respective exit from the container.

[00121] In certain applications, preferably the main surface of the substrate is coated with one or more functional coatings before deposition of the coating containing silanol groups on the respective surface. Such functional coatings classically used in optics may be, without limitation, a primer layer to improve shock resistance and/or adhesion of subsequent layers in the final product, an anti-abrasion and/or anti-scratch coating, a polarized coating, a photochromic coating or a colored coating, particularly a primer layer coated with an anti-abrasion and/or anti-scratch layer. These last two coatings are described in more detail in applications WO 2008/015364 and WO 2010/109154.

[00122] The article according to the present invention may also include coatings formed on the interferential coating, capable of modifying the respective surface properties, such as a hydrophobic and/or oleophobic coating (anti-dirt top coat) or an anti-dirty coating. -fogging. These coatings are preferably deposited on the outer layer of the interferential coating. The respective thickness is generally less than or equal to 10 nm, preferably 1 nm to 10 nm, particularly 1 nm to 5 nm. They are respectively described in applications WO 2009/047426 and WO 2011/080472.

[00123] The hydrophobic and/or oleophobic coating is preferably a fluorosilane or fluorosilazane type coating. It can be obtained by deposition of a fluorosilane or a precursor fluorosilazane, preferably comprising at least two hydrolysable groups per molecule. The precursor fluorosilanes preferably contain fluoropolyether groups and particularly perfluoropolyether groups.

[00124] Preferably, the hydrophobic and/or oleophobic outer coating has a surface energy equal to or less than 14 mJ/m2, preferably equal to or less than 13 mJ/m2, particularly equal to or less than 12 mJ/m2. The surface energy is calculated according to the Owens-Wendt method described in the reference: «Estimation of the surface force energy of polymers», Owens D. K., Wendt R. G. (1969), J. Appl. Polym. Sci., 13, 1741-1747.

[00125] The compounds that can be used to obtain said coatings are described in patents JP2005187936 and US6183872.

[00126] Commercial compositions that allow the preparation of hydrophobic and/or oleophobic coatings are the KY130® composition from Shinnetsu or the OPTOOL DSX® composition, marketed by DAIKIN INDUSTRIES.

[00127] Typically, an article according to the present invention comprises a substrate successively coated with a layer of adhesion and/or anti-shock primer, with an anti-abrasion and/or anti-scratch coating, with an interferential coating of according to the present invention, optionally antistatic, and with a hydrophobic and/or oleophobic coating.

[00128] The present invention is illustrated, in a non-limiting way, by the following examples. Unless otherwise stated, refractive indices are given for a wavelength of 630 nm and T = 20 °C-25 °C.

[00129] EXAMPLES

[00130] General procedures

[00131] The articles used in the examples comprise an ORMA® ESSILOR lens substrate measuring 65 mm in diameter, with a power of -2.00 diopters and a thickness of 1.2 mm, coated on its concave face with the anti-inflammatory primary coating. -shock and with the anti-abrasion and anti-scratch coating (hard coat) disclosed in the experimental part of the application WO 2010/109154, with an anti-reflective coating and with the anti-dirt coating disclosed in the experimental part of the application WO 2010/ 109154.

[00132] The layers of the anti-reflective coating were deposited without heating the substrates by evaporation under vacuum, possibly, when specified, assisted by a beam of oxygen ions and possibly argon during deposition (evaporation source: electron gun).

[00133] The vacuum deposition structure is a Leybold LAB 1100 + machine equipped with an electron gun for evaporation of precursor materials, a thermal evaporator, a KRI EH 1000 F ion gun (from Kaufman & Robinson Inc.) for the preliminary phase of preparation of the substrate surface by argon ions (IPC), as well as for the deposition of layer A or ion-assisted layers (IAD) and with a liquid introduction system, used when the layer precursor compound A is a liquid under normal temperature and pressure conditions (in the case of OMCTS). This system comprises a reservoir for the liquid precursor compound of layer A, a liquid flow meter and a vaporizer that is located in the machine and that is brought to reach a temperature in the range of 80° C - 200° C during its use, in function of the flow rate of the gaseous precursor, which preferably varies in the range of 0.1 g/min to 0.8 g/min (the temperature is 180° C for a flow rate of 0.3 g/min). The precursor vapor comes out of a copper tube inside the machine, at a distance of approximately 50 cm from the ion gun. An oxygen debt is introduced inside the ion gun.

[00134] The A layers according to the present invention are formed by evaporation under ion bombardment of octamethylcyclotetrasiloxane, supplied by ABCR.

[00135] The B layers according to the present invention, when present, are formed by evaporation of silicon supplied by Optron, Inc..

[00136] The thickness of the deposited layers was controlled in real time using a quartz microbalance. Unless otherwise stated, thicknesses mentioned are physical thicknesses. Several samples were prepared from each cup.

[00137] 2. Operating modes

[00138] The process of preparing the optical articles according to the present invention comprises introducing the substrate coated with the primer coating and the anti-abrasion coating defined above into the vacuum deposition container, a primary pumping step, followed by a secondary pumping for 400 s allowing a secondary vacuum to be obtained (~2.10-5 mbar, pressure read with a Bayard-Alpert type gauge), a stage of pre-heating the vaporizer to the chosen temperature (~5 min), a stage activation of the substrate surface by a beam of argon ions (IPC: 1 minute, 100 V, 1 A, with the ion gun stopped at the end of this stage), followed by the deposition by evaporation of the following inorganic layers with the aid of the electron gun until the desired thickness is obtained for each layer:

[00139] - a 20 nm thick ZrO2 layer;

[00140] - a 25 nm thick SiO2 layer;

[00141] - an 80 nm thick ZrO2 layer;

[00142] - an electrically conductive layer of ITO deposited with the assistance of oxygen ions 6 nm thick.

[00143] The deposition of layer A on the ITO layer is carried out as follows.

[00144] The ion gun is separated with argon, oxygen is added to the ion gun, with a programmed flow rate, the desired anode current (3 A) is programmed and the OMCTS compound is introduced into the container (programmed net flow of 0 .3 g/min).

[00145] The OMCTS feed is stopped when the desired thickness is reached and the ion gun is turned off.

[00146] In examples 1 and 3 to 7 (embodiment 1), an anti-dirt coating layer (top coat) (Daikin's Optool DSX®) in the order of 5 nm is deposited directly on an 80 nm layer A thick, which constitutes the outer layer of the anti-reflective coating.

[00147] In examples 2 and 8 to 13 (embodiment 2), a 5 nm - 40 nm thick silicon layer (layer B) is deposited on a 45 nm - 75 nm thick layer A (of the same so that the 1st silicon layer of the anti-reflection coating is already deposited, without ionic assistance), where the sum of the thicknesses of layers A and B is equal to 80 nm, followed by an anti-dirt coating layer (top coat) (Daikin's Optool DSX®) in the order of 5 nm is deposited on this silicon layer.

[00148] Finally, a ventilation step is carried out.

[00149] Comparative example 1 differs from the stacking of embodiments 1 and 2 described above in that layer A or the set of layer A + layer B is replaced by a silicon layer with the same thickness (80 nm) .

[00150] Comparative example 2 differs from examples 1 and 3 to 7 in that the outer layer of the anti-reflective coating was formed by co-evaporation of OMCTS (programmed net flow of 0.1 g/min) and silicon (fixed power, electron gun operated with an emission current of 60 mA with ion assistance). This outer layer of the anti-reflective coating, which is obtained from an organic substance and an inorganic substance, is prepared in accordance with US patent disclosure 6,919,134.

[00151] 3. Characterizations

[00152] Colorimetric measurements of tone angle h* and chroma C* were carried out with a Zeiss spectrophotometer and calculated in the CIE system (L*, a*, b*).

[00153] Abrasion resistance was evaluated by determining the BAYER ASTM (Bayer sand) values on the substrates coated with the anti-reflective coating and the anti-dirt coating according to the methods described in application WO 2008/001011 (ASTM F standard 735.81). The higher the value obtained in the Bayer test, the higher the abrasion resistance. Thus, the Bayer ASTM (Bayer sand) value is considered good when it is greater than or equal to 3.4 and less than 4.5 and excellent with values of 4.5 or more.

[00154] The qualitative test known as the “n x 10 blows” test allows evaluating the adhesion properties of a film deposited on a substrate, namely the adhesion of an anti-reflective coating to an ophthalmic lens substrate. It was performed on the concave face of the lenses following the procedure described in international application WO 2010/109154.

[00155] The critical temperature of the article is measured as indicated in application WO 2008/001011. It is measured one week after preparing this article.

[00156] Corrosion resistance is evaluated with the aid of an immersion test in salt water (200 g/l) at 50 °C. The lens is impregnated for 20 min and then, after drying, the visual appearance of the coating is evaluated. In particular, possible delamination defects are considered, as well as changes in the color of the anti-reflection. Classification 1 corresponds to a slight change in color and classification 2 corresponds to the absence of any detectable change.

[00157] The curvature resistance test allows evaluating the capacity of an article having a curvature subject to mechanical deformation.

[00158] The test is carried out on an initially spherical lens that has been cut to form a rectangle measuring 50 mm x 25 mm.

[00159] The request mode for this test is representative of the optical request for mounting the lens, that is, the “compression” of the lens to insert it into a metal frame. This test uses an Instron bench to apply a controlled deformation to the lens, electroluminescent diodes (LED) to illuminate the lens, a camera and image analysis software. The coated lens is compressed by the Instron bench, by applying forces exerted following the axis of the main length of the ground lens until the appearance of cracks perpendicular to the direction of displacement in the anti-reflective coating, detected by transmission image analysis. The result of the test is the critical deformation D in mm that a lens can be subjected to before cracks appear, represented in figure 1. This test is carried out one month after preparing the lenses. The higher the deformation value, the better the resistance to mechanical deformation applied.

[00160] In general, the interferential coatings according to the present invention present critical deformation values that vary in the range of 0.7 mm to 1.2 mm, particularly from 0.8 mm to 1.2 mm and particularly preferably from 0.9 mm to 1.2 mm.

[00161] 4. Results

[00162] Table 1 below presents the optical performances of different anti-reflective coatings (where the instant t designates the moment at which the preparation of the article was completed).

[00163] Table 1

[00164] Instant t = moment at which the preparation of the article is completed, upon leaving the deposition container.

[00165] The articles according to the present invention have better optical stability, particularly the chroma is much more stable over time. The article in comparative example 1 suffers a chroma decrease over time greater than 2, which is unacceptable.

[00166] Table 2 below indicates the thicknesses of layers A and B for each of examples 3 to 13, the deposition conditions of layer A (respective argon and O2 flow rates in the ion gun) as well as the test results to the which prepared articles were subject.

[00167] Table 2

[00168] Layer A of example 4 has the following atomic contents: 22% silicon, 40.8% oxygen, 20.5% carbon and 16.7% hydrogen. The outer layer of the anti-reflective coating of comparative example 2, obtained by co-evaporation of silicon and OMCTS, has the following atomic contents: 28.2% silicon, 61.5% oxygen, 3% carbon and 10 .3% hydrogen.

[00169] Articles according to the present invention present a clearly improved critical temperature and a significant improvement in the bending deformation to which the article can be subjected before cracks appear. These improvements can be directly attributed to the presence of an A layer in the anti-reflective stack, as demonstrated by comparing the examples according to the present invention with comparative example 1.

[00170] Corrosion resistance is generally improved by the presence of an A layer.

[00171] The lenses of all examples and comparative examples successfully pass the test called “n x 10 strokes”. This demonstrates that the different layers of the anti-reflective coating according to the present invention have good adhesion properties, particularly at the interface with the substrate.

[00172] The inventors found that embodiment 2 (examples 8-13) makes it possible to achieve an article having a clearly more active anti-dirt coating than that of embodiment 1 (examples 3-7), which can be verified by carrying out the ink test (“Magic Ink”) described in application WO 2004/111691, preserving good mechanical properties.

[00173] It was also found that the use of an addition of argon ions in addition to oxygen ions in the ion beam improved the cosmetic appearance of the lenses, preventing the appearance of surface defects over time, particularly visible to the arc lamp .

Claims (21)

1. Article comprising a substrate having at least one main surface coated with a multilayer interferential coating, said coating comprising a layer A having a refractive index less than or equal to 1.55, characterized by the fact that: - said layer A is a intermediate layer, which is directly in contact with the outer layer of the interferential coating, said outer layer of the interferential coating being a layer B having a refractive index less than or equal to 1.55; - and said layer A was obtained by deposition, by ion beam, of activated species from at least one compound C, in gaseous form, containing in the respective structure at least one silicon atom, at least one atom of carbon, and at least one hydrogen atom and, optionally, at least one nitrogen atom and/or at least one oxygen atom, the deposition of said layer A being carried out in the presence of nitrogen and/or oxygen when the compound C does not contain nitrogen and/or oxygen, the deposition of said A layer being carried out by bombardment by means of an ion beam on the A layer while it is being formed, - said A layer is not formed from inorganic precursor compounds, - a hydrophobic and/or oleophobic coating is applied to the outer layer of the interferential coating. 2. Article according to claim 1, characterized by the fact that the total thickness of the interferential coating is less than or equal to 1μm. 3. Article according to any one of claims 1 or 2, characterized by the fact that compound C comprises at least one silicon atom carrying at least one alkyl group. 4. Article according to any one of claims 1 to 3, characterized by the fact that compound C comprises at least one group of formula: wherein R1 to R4 independently represent alkyl groups. 5. Article according to any one of claims 1 to 4, characterized in that compound C is chosen from octamethylcyclotetrasiloxane and hexamethyldisiloxane. 6. Article according to any one of claims 1 to 5, characterized in that the silicon atom(s) of compound C do not contain a hydrolyzable group. 7. Article according to any one of claims 1 to 6, characterized in that layer A does not contain a distinct phase of metallic oxides. 8. Article according to any one of claims 1 to 7, characterized in that layer B comprises at least 50% by mass of silicon, in relation to the total mass of layer B. 9. Article according to any one of claims 1 to 8, characterized in that layer A has a thickness in the range of 20 nm to 150 nm. 10. Article according to any one of claims 1 to 9, characterized in that layer B has a thickness in the range of 2 nm to 60 nm. 11. Article according to any one of claims 1 to 10, characterized in that the interferential coating comprises low refractive index layers and that all of these low refractive index layers are inorganic in nature with the exception of layer A. 12. Article according to any one of claims 1 to 11, characterized in that all layers of the interferential coating are inorganic in nature, with the exception of layer A. 13. Article according to any one of claims 1 to 12, characterized by the fact that it is an ophthalmic lens. 14. Article according to any one of claims 1 to 13, characterized in that the interferential coating is an anti-reflective coating. 15. Article according to any one of claims 1 to 14, characterized in that the total thickness of the interferential coating is less than 800 nm. 16. Article according to any one of claims 1 to 15, characterized in that layer B comprises at least 90% by mass of silicon, in relation to the total mass of layer B. 17. Article according to any one of claims 1 to 16, characterized in that layer A has a refractive index greater than or equal to 1.47. 18. Article according to any one of claims 1 to 17, characterized in that the surface energy of the hydrophobic and/or oleophobic layer is less than 12 mJ/m2. 19. Article according to any one of claims 1 to 18, characterized in that the hydrophobic and/or oleophobic coating is formed from a fluorosilane or fluorosilazane compound. 20. Article according to any one of claims 1 to 19, characterized in that Layer A is deposited without assistance by a plasma at the substrate level. 21. Process for manufacturing an article as defined in any one of claims 1 to 20, comprising at least the following steps: - providing an article comprising a substrate having at least one main surface; - depositing on said main surface of the substrate a multilayer interferential coating, said coating comprises a layer A having a refractive index lower than or equal to 1.55, which is: an intermediate layer, which is directly in contact with the outer layer of the interferential coating, said outer layer of the interferential coating being a layer B having a refractive index less than or equal to 1.55, - depositing a hydrophobic and/or oleophobic coating on the outer layer of the interferential coating, - recovering an article comprising a substrate having a main surface coated with said interferential coating comprising said layer A, characterized in that said layer A has been obtained by deposition, by ion beam, of activated species obtained from at least one compound C, in gaseous form, containing in its structure at least one silicon atom, at least one carbon atom and at least one hydrogen atom and, optionally, at least one nitrogen atom and/or at least one oxygen atom , the deposition of said layer A being carried out in the presence of nitrogen and/or oxygen when compound C does not contain nitrogen and/or oxygen, the deposition of said layer A being carried out by bombardment by means of a beam of ions to layer A while it is being formed, and said layer A is not formed from inorganic precursor compounds.