Articles with improved thermomechanical properties featuring an organic-inorganic layer

Description

[0001] The present invention relates in general to an article, preferably an optical article, in particular an ophthalmic lens, having an interference coating comprising at least one layer of an organic-inorganic nature, preferably an anti-reflective coating or an optical filter, whose thermomechanical properties have been improved.

[0002] It is known to coat optical articles such as ophthalmic lenses or screens with interference coatings, including anti-reflective coatings, which are generally formed from a multilayer stack of dielectric mineral materials such as SiO, SiO2, Si3N4, TiO2, ZrO2, Al2O3, MgF2 or Ta2O5.

[0003] One of the problems encountered with all types of mineral interference coatings, generally deposited by vacuum evaporation or spraying, is their high mechanical fragility, primarily due to their mineral nature. These coatings are subjected to varying degrees of stress and can hardly withstand significant deformation or expansion, as the stress often results in adhesion problems and / or cracking that propagates across the entire surface of the coating, generally rendering it unusable, especially with thicker layers.

[0004] Thus, during the cutting and mounting of lenses at the optician's, the lens undergoes mechanical deformations that can cause cracks in the interference coatings, particularly when the operation is not carried out carefully. Similarly, temperature fluctuations (heating the frame) can cause cracks in the interference coating. Depending on the number and size of the cracks, these can impair the wearer's vision and prevent the lens from being sold. Furthermore, scratches can appear during the wearing of treated organic lenses. In mineral interference coatings, some scratches lead to cracking, making the scratches more visible due to light scattering.

[0005] The fragility of an interference coating from a mechanical point of view is greater the thicker it is and / or the more layers it has; a high thickness of interference coating can result from the use of thick layers or a large number of layers.

[0006] However, the design of efficient optical filters generally requires stacks with these characteristics. These thick and / or complex structures generally lead to poor thermomechanical and abrasion performance due to the nature of the deposited inorganic layers, which are thermomechanically fragile.

[0007] EP1306695-A2 and EP1324078-A2 disclose lenses having an organic substrate with a main surface coated with an organic-inorganic sublayer and an interference coating.

[0008] Application WO 2013 / 098531, filed on behalf of the applicant, describes an article having improved thermomechanical performance, comprising a substrate having at least one principal surface coated with a multilayer interference coating, said coating comprising a layer A not formed from inorganic precursor compounds having a refractive index less than or equal to 1.55, which constitutes: either the outer layer of the interference coating, or an intermediate layer, directly in contact with the outer layer of the interference coating, this outer layer of the interference coating being in this second case an additional layer having a refractive index less than or equal to 1.55, and said layer A having been obtained by deposition, under an ion beam, of activated species from at least one precursor compound C in gaseous form of a silico-organic nature such as octamethylcyclotetrasiloxane (OMCTS).

[0009] Application WO 2014 / 199103, on behalf of the applicant, describes a multilayer interference coating obtained by a similar technology, the outer layer of which is an A layer obtained by deposition, under an ion beam, of activated species from at least one precursor compound in gaseous form of a silico-organic nature such as 2,4,6,8-tetramethylcyclotetrasiloxane (TMCTS).

[0010] However, these last two requests do not concern the preparation of thick interference coatings and / or coatings with a large number of layers.

[0011] One aim of the invention is to provide an effective means of satisfactorily reducing the inherent fragility of thick mineral interference coatings (for example having thick layers) and / or having a large number of layers and significantly increasing the temperature or stress beyond which the expansion or deformation of the coating causes it to crack, in particular for the purpose of achieving complex stacking such as that required by optical filters.

[0012] The invention relates in particular to articles having an improved critical temperature, that is to say, exhibiting good resistance to cracking when subjected to a temperature rise. Another objective of the invention is to provide a simple, easy-to-implement, and reproducible method for manufacturing an article equipped with an interference coating.

[0013] These problems are solved according to the invention by modifying the nature of one or more inorganic layers of the interference coating, replacing them with one or more layers of an organic-inorganic nature, that is, layers based on carbon and metallic or metalloid compounds. According to the invention, these materials are used in place of traditional inorganic materials such as titanium dioxide, zirconium dioxide, or silica in thick interference coatings and / or coatings with a large number of layers.

[0014] The stated goals are therefore achieved according to the invention described in claim 1.

[0015] In this application, where an article includes one or more coatings on its surface, the expression "deposit a layer or coating on the article" means that a layer or coating is deposited on the exposed surface of the article's outer coating, i.e., its coating furthest from the substrate.

[0016] A coating that is "on" a substrate or that has been deposited "on" a substrate is defined as a coating that (i) is positioned above the substrate, (ii) is not necessarily in contact with the substrate (although preferably it is), meaning that one or more intermediate coatings may be placed between the substrate and the coating in question, and (iii) does not necessarily completely cover the substrate (although preferably it does). When "a layer 1 is located under a layer 2," it is understood that layer 2 is farther from the substrate than layer 1.

[0017] The article prepared according to the invention comprises a substrate, preferably transparent, having front and rear principal faces, at least one of said principal faces having an interference coating comprising at least one organic-inorganic layer, preferably both principal faces. An organic-inorganic layer is defined as a layer comprising carbon atoms, a metal or metalloid, and preferably oxygen. According to the invention, it is obtained by vacuum deposition.

[0018] The back face (generally concave) of the substrate refers to the face that, when the item is in use, is closest to the wearer's eye. Conversely, the front face (generally convex) of the substrate refers to the face that, when the item is in use, is furthest from the wearer's eye.

[0019] Although the article according to the invention may be any article, such as a screen, glazing, safety glasses for use in work environments, a mirror, or an article used in electronics, it preferably constitutes an optical article, particularly for use in the field of ophthalmology or precision optics, for example an optical filter, an optical lens, an ophthalmic lens, corrective or not, for eyeglasses, or a blank of an optical or ophthalmic lens such as a semi-finished optical lens, in particular a spectacle lens. The lens may be a polarized, colored, photochromic, or electrochromic lens.

[0020] The substrate of the article according to the invention is preferably an organic glass, for example made of thermoplastic or thermosetting plastic. This substrate can be chosen from among the substrates mentioned in application WO 2008 / 062142, for example a substrate obtained by (co)polymerization of bis-allyl carbonate of diethylene glycol, a poly(thio)urethane substrate, a polyepisulfide-based substrate or a bis(phenol A) polycarbonate (thermoplastic) substrate, denoted PC, or a PMMA (polymethyl methacrylate) substrate.

[0021] The interference coating according to the invention can be formed on at least one of the main faces of a bare substrate, i.e. uncoated, or on at least one of the main faces of a substrate already coated with one or more functional coatings.

[0022] Before the interference coating is deposited onto the substrate, which may be coated with, for example, an abrasion-resistant and / or scratch-resistant coating, it is common practice to subject the surface of the substrate, if coated, to a physical or chemical activation treatment designed to increase the adhesion of the coating. This pretreatment is generally carried out under vacuum. It may involve bombardment with energetic and / or reactive species, for example, an ion beam ("Ion Pre-Cleaning" or "IPC") or an electron beam, corona discharge treatment, effluvium treatment, UV treatment, or vacuum plasma treatment. It may also involve acid or basic surface treatment and / or solvent treatment (water or organic solvent). These treatments are described in more detail in application WO 2014 / 199103.

[0023] The article according to the invention comprises an interference coating including at least one organic-inorganic layer, which constitutes either a low refractive index layer of the multilayer interference coating, in particular anti-reflective, or a high refractive index layer.

[0024] In this application, a layer, in particular a layer of the interference coating, is said to be a high refractive index layer when its refractive index is greater than 1.65, preferably greater than or equal to 1.70, better greater than or equal to 1.8 and even better greater than or equal to 2.0, and a layer is said to be a low refractive index layer when its refractive index is less than or equal to 1.65, preferably less than or equal to 1.55, better less than or equal to 1.50 and even better less than or equal to 1.45.

[0025] The interference coating can be any interference coating classically used in the field of optics, in particular ophthalmic optics, except that it comprises at least one layer with a refractive index greater than 1.65 and at least one layer with a refractive index less than or equal to 1.65, that at least one of its layers is an organic-inorganic layer that has been deposited under vacuum, and that it complies with the thickness and / or number of layers conditions mentioned above.

[0026] The interference coating may be, without limitation, an optical filter, an anti-reflective coating, a reflective coating (mirror), preferably a selective optical filter and / or an anti-reflective coating, including an infrared filter, an ultraviolet filter (preferably an anti-UV anti-reflective coating), preferably a selective optical filter with a filtration zone in the blue range (400-500 nm). Such a filter at least partially blocks blue light, which is harmful to the wearer's eye.

[0027] An anti-reflective coating is defined as a coating, applied to the surface of an article, that improves the anti-reflective properties of the final article. It reduces the reflection of light at the article-air interface over a relatively wide portion of the visible spectrum.

[0028] As is well known, interference coatings, preferably antireflective coatings, classically comprise a stack of dielectric materials forming high refractive index (HI) layers and low refractive index (BI) layers.

[0029] HI layers are classic high refractive index layers, well known in the technique. They generally comprise one or more mineral oxides such as, without limitation, zirconia (ZrO2), titanium dioxide (TiO2), tantalum pentoxide (Ta2O5), neodymium oxide (Nd2O5), hafnium oxide (HfO2), praseodymium oxide (Pr2O3), praseodymium titanate (PrTiO3), La2O3, Nb2O5, Y2O3, indium oxide In2O3, or tin oxide SnO2. The preferred materials are TiO2, Ta2O5, PrTiO3, ZrO2, SnO2, In2O3 and their mixtures.

[0030] BI layers are also well known and may include, without limitation, SiO₂, MgF₂, ZrF₄, alumina (Al₂O₃) in small proportions, AlF₃, and mixtures thereof, preferably SiO₂. SiOF (fluorine-doped SiO₂) layers may also be used. Ideally, the interference coating of the invention does not include any layer comprising a mixture of silica and alumina.

[0031] The total thickness of the interference coating is generally greater than 100 nm, preferably greater than one of the following values: 450 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 micrometer, 1.1 micrometer, 1.2 micrometer.

[0032] Preferably, the total thickness of the interference coating is less than or equal to 2 micrometers, preferably less than or equal to 1.5 µm. In one embodiment, the total thickness of the interference coating is less than or equal to 450 nm. In this case, the interference coating necessarily has a number of layers greater than or equal to 8.

[0033] The process of the invention is particularly advantageous for depositing thick multilayer interference coatings, or coatings with thick layers or a high number of layers. Indeed, interference stacks of this type are naturally more fragile from a mechanical point of view. The fact that a thick multilayer interference coating, or one with thick layers or a high number of layers, includes at least one organic-inorganic layer according to the invention allows it to have superior thermomechanical and elastic properties, in particular improved deformation properties.

[0034] Preferably, the interference coating, which is preferably an antireflective coating, comprises at least two low refractive index (LI) layers and at least two high refractive index (HI) layers. Preferably, the total number of layers of the interference coating is greater than or equal to 8, more preferably greater than or equal to 9, and even more preferably greater than or equal to 10. In some embodiments, the total number of layers of the interference coating is less than 8, or even less than or equal to 6, but in this case, the interference coating necessarily has a thickness greater than or equal to 450 nm.

[0035] Preferably, the interference coating simultaneously has a thickness greater than or equal to 450 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 micrometer, 1.1 micrometer or 1.2 micrometer and a number of layers greater than or equal to 8, 9 or 10.

[0036] It is not necessary for the HI and BI layers to alternate in the interference coating, although they may be so according to one embodiment of the invention. Two (or more) HI layers may be deposited one on top of the other, just as two (or more) BI layers may be deposited one on top of the other.

[0037] The organic-inorganic layer of the interference coating preferably comprises carbon atoms, oxygen atoms, and a metal or metalloid selected from silicon, zirconium, titanium, and niobium, preferably silicon. In the latter case, it constitutes a silico-organic layer. It is preferably obtained by deposition of at least one organosilicon compound under vacuum. The deposition of the organic-inorganic layer is preferably assisted by an ion source. The assistance provided by the ion source is preferably ion bombardment, generally carried out by an ion gun. A layer formed from an organosilicon compound constitutes an organic-inorganic layer insofar as the deposition process is such that the deposited layer comprises carbon atoms, oxygen atoms, and a metal or metalloid.

[0038] In this application, metalloid oxides are considered to be metal oxides, and the generic term "metal" also refers to metalloids.

[0039] In one embodiment, all the low-refractive-index layers of the interference coating are organic-inorganic layers, either identical or different. In another embodiment, the outermost layer of the multilayer interference coating, that is, the layer of the interference coating furthest from the substrate in the stacking order, is an organic-inorganic layer with a low refractive index. An organic-inorganic layer with a low refractive index (having a refractive index less than or equal to 1.65), denoted layer A, is preferably deposited directly on a layer with a high refractive index.

[0040] Preferably, the outer layer of the interference coating is a low-refractive-index layer that is preferably in direct contact with an underlying high-refractive-index layer. In another embodiment, all the high-refractive-index layers of the interference coating are organic-inorganic layers, either identical or different. In some articles of the invention, the first layer of the interference coating, in the order of deposition, is a high-refractive-index organic-inorganic layer. A high-refractive-index organic-inorganic layer according to the invention (having a refractive index greater than 1.65) is denoted layer B.

[0041] According to a preferred embodiment, all layers of the interference coating are organic-inorganic layers. In this case, the interference coating can be composed of alternating layers A and B according to the invention in direct contact with each other.

[0042] According to another embodiment, all layers of the interference coating comprise at least one organosilicon compound which can be chosen from the organosilicon compounds described below.

[0043] According to the preferred embodiment of the invention, the organic-inorganic layer is a low-refractive-index layer (having a refractive index less than or equal to 1.65, preferably less than or equal to 1.55), denoted layer A, which is preferably obtained by vacuum deposition, as appropriate, of one or two categories of precursors in gaseous form, in particular by evaporation or co-evaporation: at least one organosilicon compound A and optionally at least one inorganic compound, which is preferably a metal oxide. The following description will generally refer to the metal oxide precursor of layer A but will also be applicable to cases where the inorganic precursor compound is not a metal oxide. This deposition is preferably assisted by an ion source (in particular an ion beam), ideally under ion bombardment.This ion beam deposition technique allows activated species to be obtained from at least one organosilicon compound A and at least one metal oxide (when present), in gaseous form.

[0044] The optional inorganic precursor compound of layer A is preferably a low-refractive-index metal oxide, an expression that has been defined previously. It can be chosen from the metal oxides and their mixtures suitable for the low-refractive-index layers described previously, or from substoichiometric metal oxides such as a substoichiometric silicon oxide, of formula SiOx, with x < 2, x preferably ranging from 0.2 to 1.2. It is preferably the oxides SiO₂ or SiO₂ or mixtures thereof, ideally SiO₂.

[0045] The refractive index of layer A is less than or equal to 1.65, preferably less than or equal to 1.50. According to embodiments of the invention, the refractive index of layer A is greater than or equal to 1.45, better greater than 1.47, better still greater than or equal to 1.48 and ideally greater than or equal to 1.49.

[0046] When a high-refractive-index inorganic layer (preferably containing at least one metal oxide with a refractive index greater than or equal to 1.8) is to be deposited on a layer A, it is preferable to interpose between these two layers a layer, designated layer C, comprising a silicon oxide and having a thickness less than or equal to 15 nm, in order to obtain better adhesion at the interface. The silicon oxide of this layer can be chosen from silica (SiO₂) and substoichiometric silicon oxides, of formula SiO₂, with x < 2, x preferably ranging from 0.2 to 1.2. These are preferably SiO₂ or SiO₂ oxides or mixtures thereof, ideally SiO₂. Preferably, layer C, deposited on and in direct contact with layer A, contains at least 50% by mass of silicon oxides (e.g. silica), relative to the total mass of layer C, better 75% or more and even better 90% or more, ideally 95% or more.In a preferred embodiment, layer C is a layer formed exclusively of silicon oxides. Layer C, when present, is a thin layer having a thickness preferably less than or equal to 10 nm, preferably ranging from 2 to 10 nm, and more preferably from 5 to 10 nm. Preferably, the content of organic or organosilicon compounds in layer C is less than 10% by mass relative to the mass of layer C, more preferably less than 5%, and even more preferably less than 1%.

[0047] According to one embodiment of the invention, the interference coating comprises a sub-layer. In this case, it generally constitutes the first layer of this interference coating in the order of layer deposition, that is to say, the layer of the interference coating that is in contact with the bare or coated substrate.

[0048] The term "undercoat" for the interference coating refers to a relatively thick coating used to improve the abrasion and / or scratch resistance of said coating and / or to promote its adhesion to the substrate. The undercoat according to the invention may be selected from those described in application WO 2010 / 109154. The undercoat may also be an organic-inorganic layer or comprise an organic-inorganic layer. In this case, said organic-inorganic layer comprising or constituting the undercoat is preferably an A layer.

[0049] Preferably, the sublayer has a thickness of 100 to 500 nm. It is preferably of exclusively mineral / inorganic nature and is preferably made up of silica SiO 2 .

[0050] In one embodiment, the organic-inorganic layer is a high-refractive-index layer, denoted layer B, which is preferably obtained by vacuum deposition of at least one high-refractive-index metal oxide and at least one organosilicon compound B. This deposition is preferably assisted by an ion source.

[0051] The metal oxide precursor of layer B is a high refractive index metal oxide, an expression that has been defined previously. It can be chosen from the metal oxides and their mixtures suitable for the high refractive index layers described previously, or from substoichiometric metal oxides such as a substoichiometric titanium or zirconium oxide, with respective formulas TiOx and ZrOx, with x < 2, x preferably varying from 0.2 to 1.2.

[0052] Preferably, this is TiO2 oxide or a substoichiometric titanium oxide such as the compounds TiO, Ti2O3 or Ti3O5, or hafnium oxide.

[0053] The use of titanium oxide is advantageous due to its high refractive index. The refractive index of TiO₂ in its rutile form is indeed on the order of 2.65 at 550 nm. Thus, the B layer can maintain a high refractive index (≥ 1.8) even if the titanium oxide is mixed with an organosilicon compound B with a lower refractive index.

[0054] Preferably, the refractive index of layer B is greater than or equal to at least one of the following values: 1.7, 1.8, 1.9, 2.0, 2.05 and ideally greater than or equal to 2.1.

[0055] The final article's B layer preferably contains at least one metal oxide having a refractive index greater than or equal to 1.8. This metal oxide may be the same as the precursor metal oxide used to form the B layer and described above, or it may be different from it, insofar as the B layer deposition process can induce a modification of the precursor metal oxide, such as oxidation. It is preferably a titanium oxide, in particular the compound TiO₂.

[0056] Layer B is formed from a material obtained by vacuum deposition, preferably with the assistance of an ion source (in particular an ion beam), preferably under ion bombardment, of two categories of precursors in gaseous form, notably by co-evaporation: at least one metal oxide and at least one organosilicon compound B. This ion beam deposition technique makes it possible to obtain activated species from at least one organosilicon compound B and at least one metal oxide, in gaseous form.

[0057] The article of the invention can be made antistatic by incorporating, preferably in the interference coating, at least one electrically conductive layer. The nature and location in the stack of the electrically conductive layer that can be used in the invention are described in more detail in application WO 2013 / 098531. It is preferably a layer 1 to 20 nm thick comprising preferably at least one metal oxide selected from tin-indium oxide (In₂O₃:Sn, tin-doped indium oxide denoted ITO), indium oxide (In₂O₃), and tin oxide (SnO₂).

[0058] The various layers of the interference coating, other than those described above, are preferentially deposited by vacuum deposition using one of the following techniques: i) evaporation, possibly assisted by an ion beam; ii) ion beam sputtering; iii) sputtering; iv) plasma-assisted chemical vapor deposition. These techniques are described in "Thin Film Processes" and "Thin Film Processes II," Vossen & Kern, Ed., Academic Press, 1978 and 1991, respectively. Vacuum evaporation is a particularly recommended technique. Preferably, the deposition of the organic-inorganic layers is carried out in a vacuum chamber equipped with an ion gun directed at the substrates to be coated, which emits a beam of positive ions generated in a plasma within the ion gun.Preferably, the ions produced by the ion gun are particles made up of gas atoms from which one or more electron(s) have been extracted, and formed from a noble gas, oxygen, or a mixture of two or more of these gases.

[0059] Since organic-inorganic layers are formed by vacuum deposition, they do not include hydrolysate of organosilicon compound and are therefore distinct from sol-gel coatings obtained by liquid means.

[0060] Precursors, namely the silico-organic compound B and the metal oxide (in the case of layer B) or the silico-organic compound A and optional inorganic compounds (in the case of layer A), are introduced or passed into a gaseous state in the vacuum chamber. They are preferably directed towards the ion beam and are activated and dissociated by the ion gun.

[0061] Without wishing to be limited by any particular theory, the inventors believe that in the case of layer B, the ion gun induces an activation / dissociation of the precursor compound B and the precursor metal oxide, forming an organic-inorganic layer containing MO-Si-CHx bonds, where M represents the metal atom of the metal oxide. They believe a similar process occurs in the case of layer A when it is formed from a metal oxide. In the absence of a metal oxide, the dissociation of precursor compounds, particularly silico-organic compounds, releases organic radicals that are deposited on the substrate.

[0062] This deposition technique using an ion gun and a gaseous precursor, sometimes referred to as "ion beam deposition", is described in particular with only organic precursors in US patent 5508368. It allows the formation of layers with low mechanical stresses.

[0063] According to the invention, preferably, the only place in the enclosure where a plasma is generated is the ion gun.

[0064] The ions can be neutralized, if necessary, before exiting the ion gun. In this case, the bombardment will still be considered ionic. Ion bombardment causes atomic rearrangement and densification in the layer being deposited, which allows it to be compacted while it is being formed and has the advantage of increasing its refractive index due to this densification.

[0065] During the implementation of the process according to the invention, the surface to be treated is preferably bombarded by ions with a current density generally between 20 and 1000 µA / cm², preferably between 30 and 500 µA / cm², and more preferably between 30 and 200 µA / cm² on the activated surface, and generally under a residual pressure in the vacuum chamber that can vary from 6 x 10⁻⁵ mbar to 2 x 10⁻⁴ mbar, and preferably from 8 x 10⁻⁵ mbar to 2 x 10⁻⁴ mbar. An argon and / or oxygen ion beam is preferably used. When a mixture of argon and oxygen is used, the Ar / O₂ molar ratio is preferably ≤ 1, more preferably ≤ 0.75, and even more preferably ≤ 0.5. This ratio can be controlled by adjusting the gas flow rates in the ion gun. The argon flow rate typically varies from 0 to 30 sccm. Preferably, no noble gases are used. The oxygen (O2) flow rate preferably varies from 5 to 30 sccm, and is higher when the flow rates of the precursor compounds in layers A and B are higher.

[0066] The ions in the ion beam, preferably from an ion gun, used during the deposition of the A and / or B layer preferably have an energy ranging from 5 to 1000 eV, better from 5 to 500 eV, preferably from 75 to 150 eV, preferably still from 80 to 140 eV, better from 90 to 110 eV. The activated species formed are typically radicals or ions.

[0067] In the event of ion bombardment during deposition, it is possible to carry out plasma treatment concurrently or not with the ion beam deposition of layers A and / or B. Preferably, the deposition of these layers is carried out without the assistance of a plasma at the substrate level.

[0068] The deposition of layers A and / or B, which can be carried out using identical or different methods, is performed in the presence of an oxygen source when the precursor compound in question (A and / or B) does not contain (or does not contain enough) oxygen atoms and it is desired that the corresponding layer contain a certain proportion of oxygen. Similarly, the deposition of layers A and / or B is carried out in the presence of a nitrogen source when the precursor compound in question (A and / or B) does not contain (or does not contain enough) nitrogen atoms and it is desired that the corresponding layer contain a certain proportion of nitrogen. Generally, it is preferable to introduce oxygen gas, possibly with a small amount of nitrogen gas, and preferably in the absence of nitrogen gas.

[0069] Besides the organic-inorganic layers, other layers of the interference coating can be deposited under ion bombardment as described above, i.e. by using bombardment by means of an ion beam of the layer being formed, preferably emitted by an ion gun.

[0070] The preferred method for vaporizing precursor materials for organic-inorganic layers under vacuum is physical vapor deposition, specifically vacuum evaporation, generally combined with heating the compounds to be evaporated. This can be achieved using evaporation systems as diverse as a Joule-effect heat source (the Joule effect being the thermal manifestation of electrical resistance) or an electron gun. For liquid or solid precursors, any other device known to those skilled in the art can also be used.

[0071] The organosilicon precursor compounds A and B are preferably introduced into the vacuum chamber in which the articles according to the invention are prepared in gaseous form, by controlling its flow rate. This means that they are preferably not vaporized inside the vacuum chamber (unlike the precursor metal oxides).

[0072] Preferably, the metal oxides used are preheated to a molten state and then evaporated. They are preferably deposited by vacuum evaporation using an electron gun to induce vaporization.

[0073] In the case of layer B, the precursor compound B and the precursor metal oxide are preferably deposited concurrently (e.g., by co-evaporation) or partially concurrently, that is, with overlapping deposition steps for both precursors. In the latter case, the deposition of one of the two precursors begins before the deposition of the other, with the deposition of the second precursor starting before the deposition of the first precursor is complete. The same applies to layer A when it is formed from an inorganic compound.

[0074] The organosilicon compounds A and B, precursors of layers A and B respectively, are organic in nature and independent of each other. They may therefore be identical or different, and their structure contains at least one silicon atom and at least one carbon atom. They preferably include at least one Si-C bond and at least one hydrogen atom. In one embodiment, compound A and / or B 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 the A and B layers (metal M, Si, O, C, H, N...) can be determined using the RBS (Rutherford Backscattering Spectrometry) or ERDA (Elastic Recoil Detection Analysis) technique.

[0076] The atomic percentage of metal atoms in layer B preferably varies from 10 to 30%. The atomic percentage of carbon atoms in layer B preferably varies from 10 to 20%. The atomic percentage of hydrogen atoms in layer B preferably varies from 10 to 30%. The atomic percentage of silicon atoms in layer B preferably varies from 10 to 20%. The atomic percentage of oxygen atoms in layer B preferably varies from 20 to 40%.

[0077] The atomic percentage of metal atoms in layer A preferably ranges from 0 to 15%. The atomic percentage of carbon atoms in layer A preferably ranges from 10 to 25%, ideally from 15 to 25%. The atomic percentage of hydrogen atoms in layer A preferably ranges from 10 to 40%, ideally from 10 to 20%. The atomic percentage of silicon atoms in layer A preferably ranges from 5 to 30%, ideally from 15 to 25%. The atomic percentage of oxygen atoms in layer A preferably ranges from 20 to 60%, ideally from 35 to 45%.

[0078] Non-limiting examples of organic compounds A and / or B, cyclic or non-cyclic, are the following compounds: octamethylcyclotetrasiloxane (OMCTS), decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, hexamethylcyclotrisiloxane, hexamethyldisiloxane (HMDSO), octamethyltrisiloxane, decamethyltetrasiloxane, dodecamethylpentasiloxane, tetraethoxysilane, vinyltrimethylsilane, hexamethyldisilazane, hexamethyldisilane, hexamethylcyclotrisilazane, vinylmethyldiethoxysilane, divinyltetramethyldisiloxane, tetramethyldisiloxane, polydimethylsiloxane (PDMS), polyphenylmethylsiloxane (PPMS) or a tetraalkylsilane such as tetramethylsilane.

[0079] Preferably, the organosilicon compound (A and / or B) comprises at least one silicon atom bearing at least one alkyl group, preferably in C1-C4, better still at least one silicon atom bearing one or two identical or different alkyl groups, preferably in C1-C4, for example the methyl group.

[0080] The preferred precursor compounds A and / or B contain a Si-O-Si group, or better, a divalent group of formula (3): where R' 1< to R' 4< independently denote linear or branched alkyl or vinyl groups, preferably in C1-C4, for example the methyl group, monocyclic or polycyclic aryl groups, hydroxyl groups, or hydrolyzable groups. Non-limiting examples of hydrolyzable groups are H groups, halogens (chloro, bromo, iodo...), alkoxy, aryloxy, acyloxy, -NR 1< R 2< where R 1< and R 2< independently denote a hydrogen atom, an alkyl group, or an aryl group, and -N(R 3< )-Si where R 3< denotes a hydrogen atom, a linear or branched alkyl group, preferably in C1-C4, or an aryl group, monocyclic or polycyclic, preferably monocyclic. Groups containing a Si-O-Si bond are not considered to be "hydrolyzable groups" within the meaning of the invention. The preferred hydrolyzable group is the hydrogen atom.

[0081] According to another embodiment, the precursor compound A and / or B corresponds to the formula: in which R' 5< R' 6< , R' 7< , R' 8< independently denote hydroxyl groups or hydrolyzable groups such as OR groups, in which R is an alkyl group.

[0082] According to a first embodiment, compound A and / or B comprises at least one silicon atom bearing two identical or different alkyl groups, preferably in C1-C4. According to this first embodiment, compound A and / or B is preferably a compound of formula (3) in which R'1< to R'4< independently designate alkyl groups, preferably in C1-C4, for example the methyl group.

[0083] Preferably, the silicon atom(s) of compound A and / or of compound B when present do not contain any hydrolyzable group or hydroxyl group in this embodiment.

[0084] The silicon atom(s) of the precursor compound A and / or B for layer A and / or B are preferably bonded only to alkyl groups and / or groups containing an -O-Si or -NH-Si chain, forming a Si-O-Si or Si-NH-Si group. Preferred precursor compounds for layer A and / or B are decamethyltetrasiloxane, HMDSO, and OMCTS.

[0085] It is preferably a cyclic polysiloxane of formula (4): where n denotes an integer from 2 to 20, preferably from 3 to 8, and R1b to R4b independently represent linear or branched alkyl groups, preferably C1-C4 (e.g., the methyl group), vinyl, aryl, or a hydrolyzable group. Preferred members belonging to this group are octa-alkylcyclotetrasiloxanes (n = 3), preferably octamethylcyclotetrasiloxane (OMCTS). In some cases, layer A and / or B is derived from a mixture of several compounds of formula (4) where n may vary within the limits indicated above.

[0086] According to a second embodiment, compound A and / or B contains in its structure at least one Si-X' group, where X' is a hydroxy group or a hydrolyzable group, which can be chosen, without limitation, from the following groups: H, halogen, alkoxy, aryloxy, acyloxy, -NR 1< R 2< where R 1< and R 2< independently designate a hydrogen atom, an alkyl group or an aryl group, and - N(R 3< )-Si where R 3< designates a hydrogen atom, an alkyl group or an aryl group.

[0087] According to this second embodiment of the invention, compound A and / or B preferably contains in its structure at least one Si-H group, i.e., constitutes a silicon hydride. Preferably, the silicon atom of the Si-X' group is not bonded to more than two non-hydrolyzable groups such as alkyl or aryl groups.

[0088] Among the X' groups, acyloxy groups preferentially have the formula -OC(O)R 4< where R 4< is an aryl group, preferably at C6-C12, possibly substituted by one or more functional groups, or an alkyl group, preferably at C1-C6, linear or branched, possibly substituted by one or more functional groups and possibly containing one or more double bonds, such as phenyl, methyl, or ethyl groups. Aryloxy and alkoxy groups have the formula -OR 5< where R 5< is an aryl group, preferably at C6-C12, possibly substituted by one or more functional groups, or an alkyl group, preferably at C1-C6, linear or branched, possibly substituted by one or more functional groups and possibly containing one or more double bonds, such as phenyl, methyl, or ethyl groups. Halogens are preferentially F, Cl, Br, or I.The X' groups of formula -NR1<R2< can denote an amino group (NH2), alkylamino, arylamino, dialkylamino, or diarylamino, with R1< and R2< independently designating a hydrogen atom, an aryl group (preferably in the C6-C12 position), possibly substituted by one or more functional groups, or an alkyl group (preferably in the C1-C6 position), linear or branched, possibly substituted by one or more functional groups and potentially containing one or more double bonds, such as phenyl, methyl, or ethyl groups. The X' groups of formula -N(R3<)-Si are attached to the silicon atom via their nitrogen atom, and their silicon atom naturally contains three other substituents, where R3< denotes a hydrogen atom, an aryl group (preferably in the C6-C12 position), possibly substituted by one or more functional groups, or a group alkyl, preferably in C1-C6, linear or branchedpossibly substituted by one or more functional groups and possibly also containing one or more double bonds, such as phenyl, methyl or ethyl groups.

[0089] The preferred acyloxy group is the acetoxy group. The preferred aryloxy group is the phenoxy group. The preferred halogen group is the Cl group. The preferred alkoxy groups are the methoxy and ethoxy groups.

[0090] In the second embodiment, compound A and / or B preferably comprises at least one silicon atom bearing at least one alkyl group, preferably linear or branched C1-C4, or more preferably at least one silicon atom bearing one or two identical or different alkyl groups, preferably C1-C4, and a group X' (preferably a hydrogen atom) directly bonded to the silicon atom, X' having the meaning indicated above. The preferred alkyl group is the methyl group. The vinyl group may also be used instead of an alkyl group. Preferably, the silicon atom of the Si-X' group is directly bonded to at least one carbon atom.

[0091] Preferably, each silicon atom of compound A and / or B is not directly bonded to more than two X' groups; better still, it is not directly bonded to more than one X' group (preferably a hydrogen atom); better still, each silicon atom of compound A and / or B is directly bonded to only one X' group (preferably a hydrogen atom). Preferably, compound A and / or B has a Si / O atomic ratio of 1. Preferably, compound A and / or B has a C / Si atomic ratio <2, preferably ≤ 1.8, better still ≤ 1.6, and better still ≤ 1.5, ≤ 1.3, and optimally equal to 1. Preferably still, compound A and / or B has a C / O atomic ratio of 1. In one embodiment, compound A and / or B does not contain a Si-N group; better still, it does not contain a nitrogen atom.

[0092] The silicon atom(s) of the precursor compound A and / or B are preferably bonded only to alkyl groups, hydrogen groups, and / or groups containing an -O-Si or -NH-Si chain, so as to form a Si-O-Si or Si-NH-Si group. In one embodiment, compound A and / or B comprises at least one Si-O-Si-X' group or at least one Si-NH-SiX' group, where X' has the meaning indicated above and preferably represents a hydrogen atom.

[0093] According to this second embodiment, compound A and / or B is preferably a compound of formula (3) in which at least one of R' 1< to R' 4< designates a group X' (preferably a hydrogen atom), X' having the meaning indicated above.

[0094] According to this second embodiment, compound A and / or B is preferably a cyclic polysiloxane of formula (5): where X' has the meaning given above and preferably represents a hydrogen atom, n denotes an integer from 2 to 20, preferably from 3 to 8, and R1a< and R2a< independently represent an alkyl group, preferably C1-C4 (e.g., the methyl group), vinyl, aryl, or a hydrolyzable group. Non-limiting examples of hydrolyzable X' groups are chloro, bromo, alkoxy, acyloxy, aryloxy, and H groups. The most common members of this group are the tetra-, penta-, and hexa-alkylcyclotetrasiloxanes, preferably the tetra-, penta-, and hexa-methylcyclotetrasiloxanes, with 2,4,6,8-tetramethylcyclotetrasiloxane (TMCTS) being the preferred compound. In some cases, layer A and / or B is made from a mixture of a number of compounds having the above formula where n can vary within the limits indicated above.

[0095] According to another embodiment, compound A and / or B is a linear alkylhydrosiloxane, preferably a linear methylhydrosiloxane such as, for example, 1,1,1,3,5,7,7,7-octamethyl tetrasiloxane, 1,1,1,3,5,5,5-heptamethyltrisiloxane, 1,1,3,3,5,5-hexamethyl trisiloxane.

[0096] Non-limiting examples of precursor organic compounds A and / or B, cyclic or non-cyclic, conforming to the second embodiment, are the following compounds: 2,4,6,8-tetramethylcyclotetrasiloxane (TMCTS of formula (1)), 2,4,6,8-tetraethylcyclotetrasiloxane, 2,4,6,8-tetraphenylcyclotetrasiloxane, 2,4,6,8-tetraoctylcyclotetrasiloxane, 2,2,4,6,6,8-hexamethylcyclotetrasiloxane, 2,4,6-trimethylcyclotrisiloxane, cyclotetrasiloxane, 1,3,5,7,9-pentamethylcyclopentasiloxane, 2,4,6,8,10-hexamethylcyclohexasiloxane, 1,1,1,3,5,7,7,7-octamethyl tetrasiloxane, 1,1,3,3,5,5-hexamethyltrisiloxane, tetramethyldisiloxane, tetraethoxysilane, vinylmethyldiethoxysilane, a hexamethylcyclotrisilazane such as 3,4,5,6-hexamethylcyclotrisilazane or 2,2,4,4,6,6-hexamethylcyclotrisilazane, 1,1,1,3,5,5,5-heptamethyl trisiloxane, tris(trimethylsiloxy)silane (of formula (2)), 1,1,3,3-tetramethyldisilazane, 1,2,3,4,5,6,7,8-Octamethylcyclotetrasilazane, nonamethyl trisilazane, tris(dimethylsilyl)amine, hexamethyldisilazane.

[0097] The use of at least one organosilicon compound B to form the B layer, which preferably includes Si-C and possibly Si-O bonds, allows for improved thermomechanical properties compared to traditional high refractive index materials such as TiO2 or ZrO2, in particular the temperature resistance and scratch resistance of substrates coated by the B layers according to the invention, for which levels are achieved that were previously unattainable by traditional technologies such as the deposition of purely inorganic layers under ion assistance, while maintaining a high refractive index and transparency.

[0098] According to one embodiment of the invention, layer B comprises more than 80% by mass of compounds derived from compound B and the metal oxide according to the invention, relative to the total mass of layer B, preferably more than 90%. In one embodiment, layer B is exclusively formed by vacuum deposition under ion bombardment of at least one metal oxide and at least one organosilicon compound B, to the exclusion of any other precursor.

[0099] Preferably, layer B contains from 5 to 90% by mass of metal oxides relative to the mass of layer B. Even more preferably, layer B contains from 5 to 70% by mass of organosilicon compounds B relative to the mass of layer B.

[0100] The inorganic precursor compounds of layer A (generally metal oxides), when present, are included in such a proportion that layer A preferably contains less than 30% by mass of inorganic compounds relative to the mass of layer A, preferably less than 20%, preferably even less than 10%, and preferably less than 5%. In a preferred embodiment, the organic-inorganic layer (which is preferably layer A) is not formed from inorganic (mineral) precursor compounds such as mineral oxides and therefore does not contain inorganic compounds such as metal oxides. Organosilicon compounds are not considered in this application to be inorganic compounds covered by this exclusion. In this case, layer A is a layer that preferably contains only organosilicon compounds.Preferably, the content of inorganic compounds or metal oxides in layer A is less than 10% by mass relative to the mass of layer A, better less than 5% and even better less than 1%.

[0101] Preferably, layer A contains more than 70% by mass of organosilicon compounds A relative to the mass of layer A, better more than 80%, even better more than 90% and ideally 100%.

[0102] The organic-inorganic layer preferably has a thickness of 20 to 500 nm, more preferably 25 to 250 nm, and better still 30 to 200 nm. In a preferred embodiment, the interference coating contains at least one organic-inorganic layer with a thickness greater than or equal to 250 nm, and better still 300 nm.

[0103] In another embodiment, the sum of the thicknesses of the organic-inorganic layers of the interference coating is greater than or equal to 250 nm, better greater than or equal to 300 nm and even better greater than or equal to 500 nm.

[0104] When it forms the outer layer of the interference coating, the organic-inorganic layer preferentially has a thickness ranging from 60 to 200 nm. The duration of the deposition process, the flow rates and pressures are adjusted to obtain the desired coating thicknesses.

[0105] The nature of the precursor compounds used, their respective quantities (which can be modulated by adjusting the evaporated flow rates), the deposition conditions, in particular the duration of the deposition, are examples of parameters that a person skilled in the art will know how to vary in order to achieve the interference coating comprising at least one organic-inorganic layer exhibiting all the desired properties.

[0106] Among its advantageous properties, the article according to the invention possesses increased resistance to bending and cracking of the interference coating. This stems from the nature of the organic-inorganic layer of the invention, which has a higher elongation at break than inorganic layers and can undergo deformation without cracking. The bending resistance of the article according to the invention can be evaluated using the bending resistance test described in application WO 2013 / 098531. The stress method used in this test is representative of the stress experienced by opticians during lens mounting, i.e., the "compression" of the lens to insert it into a metal frame. The result of the test is the critical deformation D in mm that the lens can undergo before cracking occurs. The higher the deformation value, the better the resistance to applied mechanical deformation.In general, the interference coatings according to the invention have critical strain values ​​ranging from 0.5 to 1.9 mm, better from 0.5 mm to 1.4 mm and even better from 0.5 to 1 mm.

[0107] The critical temperature of a coated article according to the invention is preferably greater than or equal to 60°C, better greater than or equal to 70°C, even better greater than or equal to 80°C, and ideally greater than or equal to 90°C. In this application, the critical temperature of an article or coating is defined as the temperature at which cracking is observed in the stack present on the surface of the substrate, indicating coating degradation. This high critical temperature is due to the presence of the organic-inorganic layer on the surface of the article. Furthermore, this layer has a lower capacity to absorb water than evaporated inorganic layers and excellent long-term stability of its optical properties.

[0108] Thanks to its improved thermomechanical properties compared to mineral coatings, the organic-inorganic layer according to the invention can be applied to only one face of a semi-finished lens, generally its front face, the other face of which still needs to be machined and treated. The stack present on the front face of the lens will not be degraded by the temperature increase generated by the treatments applied to the back face during the hardening of the coatings deposited on this back face, or by any other action likely to increase the lens temperature.

[0109] Preferably, the average reflectance factor in the visible range (400-700 nm) of an article coated with an interference coating according to the invention, denoted Rm, is less than 2.5% per face, better less than 2% per face, and even better less than 1% per face of the article. In an optimal embodiment, the article comprises a substrate whose two principal surfaces are coated with an interference coating according to the invention and has a total Rm value (cumulative reflectance due to the two faces) of less than 1%. The means for achieving such Rm values ​​are known to those skilled in the art.

[0110] In this application, the "average reflection factor" Rm (average of spectral reflection over the entire visible spectrum between 400 and 700 nm) is as defined in ISO 13666:1998, and measured in accordance with ISO 8980-4.

[0111] In certain applications, it is preferable for the main surface of the substrate to be coated with one or more functional coatings prior to the deposition of the interference coating. These functional coatings, commonly used in optics, may include, but are not limited to, a primer layer that improves impact resistance and / or the adhesion of subsequent layers in the final product, an abrasion-resistant and / or scratch-resistant coating, a polarized coating, a photochromic, electrochromic, or colored coating, and in particular, a primer layer coated with an abrasion-resistant and / or scratch-resistant coating. These last two coatings are described in more detail in applications WO 2008 / 015364 and WO 2010 / 109154.

[0112] The article according to the invention may also include coatings formed on the interference coating, capable of modifying its surface properties, such as a hydrophobic and / or oleophobic coating (anti-fouling top coat) or an anti-fog coating. These coatings are preferably deposited on the outer layer of the interference coating. Their thickness is generally less than or equal to 10 nm, preferably from 1 to 10 nm, and more preferably from 1 to 5 nm. They are described respectively in applications WO 2009 / 047426 and WO 2011 / 080472.

[0113] Typically, an article according to the invention comprises a substrate successively coated with an adhesion and / or shock-absorbing primer layer, an abrasion and / or scratch-resistant coating, a multilayer interference coating comprising at least one organic-inorganic layer, and a hydrophobic and / or oleophobic coating.

[0114] The invention also relates to a method for manufacturing an article as defined above, comprising at least the following steps: to provide an article comprising a substrate having at least one principal surface, to deposit on said principal surface of the substrate a multilayer interference coating comprising at least one layer having a refractive index greater than 1.65 and at least one layer having a refractive index less than or equal to 1.65, at least one of the layers of the interference coating being an organic-inorganic layer having been deposited under vacuum and having a thickness greater than or equal to 30 nm, said interference coating having a thickness greater than or equal to 450 nm and / or a number of layers greater than or equal to 8, to retrieve an article comprising a substrate having a principal surface coated with said interference coating.

[0115] The invention is illustrated, in a non-limiting way, by the following examples. EXAMPLES 1. General Procedures

[0116] The articles used in the examples include an ORMA ®< ESSILOR lens substrate of 65 mm in diameter, of power -2.00 diopters and of center thickness 1.2 mm, coated on its concave face with the shock-resistant primer coating and the abrasion-resistant and scratch-resistant coating (hard coat) disclosed in the experimental part of application WO 2010 / 109154, and an anti-reflective interference coating comprising a layer A according to the invention.

[0117] The vacuum deposition system is a Leybold LAB1100+ machine equipped with an electron gun for the evaporation of precursor materials, a thermal evaporator, a KRI EH 1000 F ion gun (from Kaufman & Robinson Inc.) for the preliminary phase of substrate surface preparation by argon ions (IPC), as well as for the deposition of layers under ion bombardment (IAD), and a liquid introduction system, used when the organosilicon precursor compound, in particular of layer A, is a liquid under normal temperature and pressure conditions (case of decamethyltetrasiloxane).This system includes a reservoir containing the liquid precursor compound of the layer in question, heating elements for the reservoir and tubes connecting the liquid precursor reservoir to the vacuum deposition machine, a flow meter for the vapor from the company MKS (MKS1150C), brought to a temperature of 30-120°C during its use, depending on the flow rate of decamethyltetrasiloxane vaporized, which preferably varies from 0.01 to 0.8 g / min (1 to 50 sccm) (the temperature is 120°C for a flow rate of 0.3 g'min (20 sccm) of decamethyltetrasiloxane).

[0118] Decamethyltetrasiloxane vapor exits a copper pipe inside the machine, at a distance of approximately 30 cm from the ion gun. Flows of oxygen and possibly argon are introduced into the ion gun. Preferably, argon or any other noble gas is not introduced into the ion gun.

[0119] The A layers according to the invention are formed by vacuum evaporation assisted by an oxygen ion beam and optionally argon during the deposition (evaporation source: electron gun) of decamethyltetrasiloxane, supplied by the company Sigma-Aldrich.

[0120] Unless otherwise stated, the thicknesses mentioned in this application are physical thicknesses. Several samples of each glass were prepared. 2. Operating procedures

[0121] The method for preparing optical articles according to the invention includes introducing the substrate coated with the primary coating and the anti-abrasion coating defined above into the vacuum deposition chamber, preheating the tank, pipes and steam flowmeter to the chosen temperature (~15 min), a primary pumping step, then a secondary pumping step for 400 s allowing obtaining a secondary vacuum (~2.10-5 mbar, pressure read on a Bayard-Alpert gauge), a step of activating the surface of the substrate by an argon ion beam (IPC: 1 minute, 100 V, 1 A, the ion gun remaining in operation at the end of this step), then the evaporation deposition of an anti-reflective coating comprising at least one layer A.

[0122] Deposition of a layer A according to the inventionThe ion gun, having been started with argon, is then supplemented with oxygen at a programmed flow rate. The desired anode current (3 A) is programmed, and the argon flow rate is optionally stopped, depending on the desired deposition conditions. Generally, the process according to the invention is carried out with oxygen (O₂ flow rate in the ion gun at the ion source: 20 sccm), in the absence of a noble gas (no argon flow rate at the ion source). Decamethyltetrasiloxane is introduced into the deposition chamber in gaseous form (injection rate: 20 sccm). The supply of this compound is stopped once the desired thickness is achieved, and then the ion gun is switched off.

[0123] The deposition of the other layers of metal oxides (containing no organosilicon compounds) was carried out in a conventional manner by vacuum evaporation of the appropriate metal oxide (zirconium oxide, SiO2 ...), without ionic assistance.

[0124] The thickness of the deposited layers was controlled in real time using a quartz crystal microbalance, adjusting the deposition rate as needed by modifying the electron gun current. Once the desired thickness was achieved, the shutter(s) were closed, the ion and electron gun(s) were switched off, and the gas flows (oxygen, possibly argon and decamethyltetrasiloxane vapors) were stopped.

[0125] A final ventilation step was carried out once the stacking had been deposited.

[0126] Several comparative examples were carried out, replacing the layer(s) A according to the invention with layers of SiO2. Thus, the stacking of comparative example 1 differs from that of examples 1 to 3 by the suppression of organosilicon compounds in the layers of the anti-reflective coating and their replacement by silica, and the stacking of comparative example 4 differs from that of example 4 by the suppression of organosilicon compounds in the layers of the anti-reflective coating and their replacement by silica.

[0127] The articles in Examples 1-4 and the comparative examples are blue light selective optical filters. The interference coating used in Examples 1-3 and Comparative Example 1 is a thick stack (1210.5 nm) comprising 5 layers with a high thickness (> 100 nm). The interference coating used in Example 4 and Comparative Example 4 is a thinner stack (510 nm) comprising a high number of layers (8). 3. Characterizations

[0128] The critical temperature of the article is measured 24 hours and / or one week after its preparation, in the manner indicated in application WO 2008 / 001011.

[0129] Unless otherwise stated, the refractive indices referred to in the present invention are expressed for a wavelength of 632.8 nm and were measured by ellipsometry at a temperature of 20-25°C.

[0130] The bending resistance test, described in application WO 2013 / 098531, assesses the ability of a curved article to withstand mechanical deformation. The result of the test, carried out one month after the glass preparation, is the critical deformation D in mm that the glass can undergo before cracking occurs. The higher the deformation value, the better the resistance to applied mechanical deformation.

[0131] The adhesion properties of the entire interference coating to the substrate were verified on the convex face of the lens using the test commonly known as the "n×10 strokes" test, following the procedure described in international patent applications WO 2010 / 109154 and WO 99 / 49097, with a number of stresses equal to 13. The test determines the number of stresses a lens can withstand before a defect appears. Therefore, the higher the value obtained in the n×10 strokes test, the better the adhesion of the interference coating to the substrate.

[0132] The abrasion resistance of the article was evaluated by determining the ASTM Bayer (Bayer sand) values ​​on substrates coated with the anti-reflective coating according to the methods described in application WO 2008 / 001011 (ASTM F 735.81). The higher the Bayer test value, the greater the abrasion resistance. Thus, the ASTM Bayer (Bayer sand) value is considered good when it is greater than or equal to 3.4 and less than 4.5, and excellent for values ​​of 4.5 and above.

[0133] The hardness, or scratch resistance, was assessed using the so-called steel wool test (pdf manual, or steel wool test), as described in application WO 2008 / 062142. The higher the score obtained (score ranging from 1 to 5), the lower the scratch resistance of the glass. 4. Results

[0134] The tables below present the optical and mechanical performance of different articles according to the invention or comparative articles as well as the deposition conditions of the different layers. Example 1 Substrate + primer + hard coat ZrO 2 13.5 nm Layer A * 404 nm SiO2 8 nm ZrO 2 153 nm SiO2 235 nm ZrO 2 277 nm SiO2 120 nm Comparative example C1 Substrate + primer + hard coat ZrO 2 13.5 nm SiO2 412 nm ZrO 2 153 nm SiO2 235 nm ZrO 2 277 nm SiO2 120 nm Example 3 Substrate + primer + hard coat ZrO 2 13.5 nm Layer A * 404 nm SiO2 8 nm ZrO 2 153 nm SiO2 235 nm ZrO 2 277 nm Layer A * 120 nm Example 2 Substrate + primer + hard coat ZrO 2 13.5 nm SiO2 412 nm ZrO 2 153 nm SiO2 235 nm ZrO 2 277 nm Layer A * 120 nm Example 4 Substrate + primer + hard coat ZrO 2 47 SiO2 50 ZrO 2 54 SiO2 69 ZrO 2 44 SiO2 61 ZrO 2 53 Layer A * 132 Comparative example C4 Substrate + primer + hard coat ZrO 2 47 SiO2 50 ZrO 2 54 SiO2 69 ZrO 2 44 SiO2 61 ZrO 2 53 SiO2 132 Layer A: Decamethyltetrasiloxane. * Ion-assisted deposition. Example Bayer ASTM Test nx10 shots test steel wool test Critical temperature [°C] at t+24h Critical temperature [°C] at t+ 1 week Resistance to bending, deformation in mm before cracking 1 6,8 13 3 60 60 0,66 C1 6,8 13 3 60 50 0,32 2 10,0 13 3 70 70 0.36 3 9,0 13 1-3 70 60 0,63 4 3,2-5,5 13 3 70-80 50-70 0,65 C4 1,6 13 3 70 50 0,44

[0135] The articles in examples 1 to 4 showed no cracking at the end of their preparation and demonstrated good performance in the various durability tests carried out. They exhibited critical temperatures 10 to 20°C higher and bending resistance 1.5 to 2 times greater compared to the articles in the comparative examples, whose anti-reflective coatings do not contain any organosilicon compounds.

[0136] The best compromise in terms of bending resistance, abrasion resistance and critical temperature performance was obtained for example 3.

[0137] The abrasion resistance of the articles in examples 2 and 3 is remarkably high.

Claims

1. An article comprising a substrate having at least one main surface coated with a multilayer interference coating comprising at least one layer having a refractive index higher than 1.65 and at least one layer having a refractive index lower than or equal to 1.65, at least one of the layers of the interference coating being a layer of organic-inorganic nature that was obtained by vacuum deposition of at least one organosilicon compound and that has a thickness higher than or equal to 30 nm, said layer of organic-inorganic nature having a refractive index lower than or equal to 1.65 and comprising more than 80 % by weight of organosilicon compounds as compared to the weight of said layer, said interference coating having: - a number of layers higher than or equal to 8, and / or - a thickness higher than or equal to 450 nm.

2. The article as claimed in claim 1, characterized in that the layer of organic-inorganic nature comprises atoms of carbon, of oxygen and of a metal or metalloid.

3. The article as claimed in any one of the preceding claims, characterized in that the layer of organic-inorganic nature is deposited under the assistance of a source of ions and preferably under ion bombardment achieved by means of an ion gun.

4. The article as claimed in any one of the preceding claims, characterized in that the organosilicon compound comprises at least one divalent group of formula: where R'1 to R'4 independently denote alkyl, vinyl, aryl or hydroxyl groups or hydrolysable groups, or in that the organosilicon compound corresponds to the formula: in which R'5, R'6, R'7 and R'8 independently denote hydroxyl groups or hydrolysable groups, such as OR groups, in which R is an alkyl group.

5. The article as claimed in any one of the preceding claims, characterized in that the organosilicon compound is chosen from octamethylcyclotetrasiloxane, 2,4,6,8-tetramethylcyclotetrasiloxane, decamethyltetrasiloxane, decamethyl cyclopentasiloxane, dodecamethylpentasiloxane, and hexamethyldisiloxane.

6. The article as claimed in any one of the preceding claims, characterized in that said layer of organic-inorganic nature is not formed from inorganic precursor compounds.

7. The article as claimed in any one of the preceding claims, characterized in that the layer of organic-inorganic nature has a refractive index lower than or equal to 1.55.

8. The article as claimed in any one of the preceding claims, characterized in that the interference coating has a thickness higher than or equal to 450 nm and a number of layers higher than or equal to 8.

9. The article as claimed in any one of the preceding claims, characterized in that the interference coating has a thickness higher than or equal to 1 µm, preferably higher than or equal to 1.1 µm.

10. The article as claimed in any one of the preceding claims, characterized in that it comprises a layer of organic-inorganic nature of thickness higher than or equal to 300 nm.

11. The article as claimed in any one of the preceding claims, characterized in that the interference coating comprises an underlayer comprising a layer of organic-inorganic nature.

12. The article as claimed in any one of the preceding claims, characterized in that the interference coating is a selective optical filter and / or an antireflection coating, preferably a selective optical filter including a filtering zone in the domain of the blue (400-500 nm).

13. The article as claimed in any one of the preceding claims, characterized in that it has a critical temperature higher than or equal to 60°C.