Optical article comprising a multilayer antireflective coating with very low reflection in the visible region, while having neutral color properties

Abstract

The present invention relates to an article having a front main face and a rear main face, comprising: at least one base element having a front main surface and a rear main surface, at least one multilayer antireflective coating, deposited on said front main surface and / or said rear main surface of the base substrate, which comprises at least two layers having a low refractive index which is lower than 1.55, defined as "LI layer", and at least two layers having a high refractive index which is equal to or higher than 1.55, defined as "HI layer", characterized in that the at least one multilayer antireflective coating is configured such that the front and / or the rear main face of the optical article has, in reflexion, - a predetermined mean light reflection factor in the visible region Rv which is lower than or equal to 1.5 %, said mean light reflection factor in the visible region Rv being as defined in the ISO 13666:1998 Standard and measured in accordance with the ISO 8980- 4, under the standard illuminant D65 and an angle of incidence of 15°, - a predetermined Chroma C*, as defined in the international colorimetric CIE L*a*b* under the standard illuminant D65, which is lower than or equal to 4 for any angle of incidence between 0° to 75°.

Description

[0001] Optical article comprising a multilayer antireflective coating with very low reflection in the visible region, while having neutral color properties

[0002] TECHNICAL FIELD OF THE INVENTION

[0003] The invention relates to an optical article comprising a base element, such as a substrate, having a front main face and a rear main face, the front main face and / or the rear main face being coated with a multilayer antireflective coating. The multilayer antireflective coating is able to and / or configured to strongly reduce reflection in the visible region, while being almost non-visible for both wearer and observers, i.e.: having neutral color properties.

[0004] The optical article may especially be an ophthalmic lens, in particular a spectacle lens.

[0005] BACKGROUND INFORMATION AND PRIOR ART

[0006] An anti refl ection coating usually consists of a multilayer comprising antireflective thin layers, generally an alternation of layers based on a dielectric material of high refractive index and a dielectric material of low refractive index. When deposited on a transparent substrate, the function of such a coating is to reduce its light reflection and therefore to increase its light transmission. A substrate thus coated will therefore have its transmitted light / reflected light ratio increased, thereby improving the visibility of objects placed behind it. When it is sought to achieve a maximum antireflection effect, it is then preferable to provide both faces (front and rear faces) of the substrate with this type of coating.

[0007] This antireflective coating is usually used in the ophthalmic field. Accordingly, traditional antireflective coatings are designed and optimized to reduce reflection on the lens surface in the visible region, typically within the spectrum range of from 380 nm to 780 nm. In general, the mean light reflection factor in the visible region Rv on the front and / or rear faces of an ophthalmic lens is between 1 .5 to 2.5%.

[0008] Some of these antireflective coatings may also be designed and optimized to reduce reflection on the lens surface within the UVA band of from 315 to 400 nm and / or the UVB band of from 280 to 315 nm. These UVA and UVB bands are indeed particularly harmful to the retina. The mean reflection in the UVA and UVB regions may thus attain high levels (up to 60%) for traditional antireflective lenses. In one hand, as regards non-solar antireflective articles which are marketed by most of the manufacturers over the course of these recent years, the UV mean reflection does range from 10 to 25%, for an angle of incidence of from 30 to 45°. It is not problematic on the front face of the lens, since the major part of the UV radiation which comes from the front of the wearer and might attain the wearer’s eye (normal incidence, 0 to 15°) generally get absorbed by the ophthalmic lens substrate. A better protection against UV radiation transmission may be obtained through solar ophthalmic lenses, which are studied and designed to reduce the visible spectrum luminosity, totally absorb UVB and totally or partially absorb UVA. On the other hand, the UV radiation resulting from light sources located behind the wearer may reflect on the lens rear face and reach the wearer’s eye if the lens is not provided with an antireflective coating which is efficient in the ultraviolet region, thus potentially affecting the wearer’s health. Such phenomenon is made stronger by the trend for fashion sunglasses with high diameters which increase the risk of stray reflections getting into the eyes. It is admitted that the light rays that may reflect onto the lens rear face and reach the wearer’s eye have a narrow incidence angle range, ranging from 30 to 45° (oblique incidence).

[0009] Also, by adding the antireflective multilayer coating and as mentioned above, this one significantly helps reducing the mirror effect and improves the wearer’s eyes visibility. However, it also introduces a collateral effect, especially a noticeable clear or color residual reflection.

[0010] Some new antireflective coatings have been developed so as to attempt to improve their aesthetic appearance, such as their optical and colorimetric characteristics.

[0011] However, it has been observed that optimizing the antireflective performances over the whole visible region reveals generally detrimental to the colorimetric performances and conversely, optimizing the colorimetric properties in the visible region does not make sure that excellent antireflective properties can be obtained in the visible region.

[0012] For instance, the antireflective multilayer coatings available on the market present a very low reflection in the visible region (i.e.: such a mean light reflection factor in the visible region Rv on the front and / or rear faces of an ophthalmic lens which is lower than or equal to 0.5%), but a detectable residual color in reflection for an observer (such as a green or blue residual reflection color) which also modifies the skin and eye coloration. This residual reflection color may be more distinguishable when the Chroma C* of these antireflective multilayer coatings is high. This residual color reflection, which is furthermore noticeable for different angles of incidence, provides a non-aesthetic and unpleasant appearance for the ophthalmic lens.

[0013] In addition, the optimization of both the optical and colorimetric characteristics of the optical article must not be detrimental to its robustness.

[0014] The term “robustness” of an optical article, such as an ophthalmic lens, in the present invention is defined as the ability of this optical article to resist change despite the variations induced by its manufacture process. These variations depend, for instance, on the type of substrate which is used, the setting of the manufacturing machine (temperature schedule, appropriate time, setting of the electron gun, humidity percentage, vacuum level in the antireflective equipment, cycle time, ...) and / or its usage mode, the replacement of said manufacturing machine by another one.

[0015] Indeed, when multilayered antireflective coatings are manufactured at industrial scale, some thickness variations for each layer generally occur. These variations lead to different reflection performance, and especially different perceived residual reflected color of the multilayered antireflective coating. If the perceived residual reflected color of the antireflective coating of two lenses is different, these lenses will appear different and will not be able to be associated in pair. Furthermore, depending on the curvatures of the lenses and the value of incidence (angle 0), the residual reflected color of the multilayered antireflective coating of each lens may not appear homogeneous in color on all the surface of the lens (“chameleon effect”). A different residual reflected color between the right and the left portions of a lens, such as a color gradient of different hues “h” (not the same color turning for instance from blue to red) or a color gradient of different color intensity (for example, turning from saturated color to a less saturated color, or inversely) may be viewed by an observer according to the incidence angle 0.

[0016] From the prior art, the following documents are known.

[0017] Document US 2017 / 235020 describes an optical article, specifically an ophthalmic lens, with an antireflective coating. The aim of this document is to provide novel antireflective coatings having very good antireflective properties at least in the visible region and possibly in the UVA and UVB bands, while having at the same time robustness properties and aesthetic appearance.

[0018] Document US 2023 / 176255 relates to an optical article, such as an ophthalmic lens, with a multilayered interferential coating that reduces reflection in both the visible and near-infrared (NIR) regions.

[0019] Document EP 4 109 141 relates to an optical lens with a light-absorbing interferential coating with improved abrasion resistance, good adhesion, and light-absorbing properties.

[0020] Therefore, an object of the current invention is thus to propose a new optical article which avoids, at least in part, the aforementioned drawbacks.

[0021] In particular, it would be desirable to improve the aesthetic appearance of such an optical article by obtaining, for instance, a clear or non-visible perceived residual reflected color of the lens surface for an observer looking at the wearer of this optical article, and this whatever the angle of incidence. As mentioned above, most of antireflection coatings developed hitherto have been optimized to minimize light reflection at normal incidence or at 15°, without taking into account the optical and aesthetic appearance of the multilayered antireflective coating seen at all oblique incidence angles and / or their robustness properties.

[0022] Thus, there is still a need to provide novel antireflective coatings having very good antireflective properties at least in the visible region and possibly in the UVA and UVB bands, while having at the same time aesthetic appearance, whatever the angle of incidence and preferably robustness properties.

[0023] SUMMARY OF THE INVENTION

[0024] The Applicant sought to develop a new transparent optical article, especially an ophthalmic lens such as spectacle lens, comprising a base element, such as a substrate in mineral or organic glass, coated on its rear main face and / or front main face with a specific multilayered coating (named hereafter “AR coating”, said AR coating having a very low reflection in the visible and preferably also in the UV bands, while having excellent colorimetric properties and especially while having a neutral or a non-discernible residual reflection color for an observer, and this whatever the angle of incidence.

[0025] For that purpose, the invention refers to an optical article having a front main face and a rear main face, comprising: at least one base element having a front main surface and a rear main surface, at least one multilayer antireflective coating, deposited on said front main surface and / or said rear main surface of the base substrate, which comprises at least two layers having a low refractive index which is lower than 1.55, defined as “LI layer”, and at least two layers having a high refractive index which is equal to or higher than 1.55, defined as “HI layer”, characterized in that the at least one multilayer antireflective coating is configured such that the front and / or the rear main face of the optical article has, in reflexion,

[0026] - a predetermined mean light reflection factor in the visible region Rv which is lower than or equal to 1.5 %, said mean light reflection factor in the visible region Rv being as defined in the ISO 13666:1998 Standard and measured in accordance with the ISO 8980-4, under the standard illuminant D65 and an angle of incidence of 15°,

[0027] - a predetermined Chroma C*, as defined in the international colorimetric CIE L*a*b* under the standard illuminant D65, which is lower than or equal to 4, preferably lower than or equal to 3 for any angle of incidence between 0° to 75°.

[0028] According to the invention, “by any angle of incidence between “x” and “y”, it includes all the angles of incidence between “x” and “y”.

[0029] In other words, here, the Chroma C* is lower than or equal to 4, preferably lower than or equal to 3 for any angle of incidence between 0° to 75° means that “whatever the angle of incidence ranging from 0° to 75°” or “for all the angles of incidence ranging from 0° to 75°”, the Chroma C* is lower than or equal to 4, preferably lower than or equal to 3.

[0030] The Applicant has found that such an antireflective coating having a low Rv and a low Chroma C* enables to provide an optical article which does not alter the face and eyes of the wearer and hence has a suitable cosmetic appearance, while having very good robustness and this whatever the angle of incidence.

[0031] The invention also relates to an eyewear device comprising at least an optical article having a front main face and a rear main face, comprising: at least one base element having a front main surface and a rear main surface, at least one multilayer antireflective coating, deposited on said front main surface and / or said rear main surface of the base substrate, which comprises at least two layers having a low refractive index which is lower than 1.55, defined as “LI layer”, and at least two layers having a high refractive index which is equal to or higher than 1.55, defined as “HI layer”, characterized in that the at least one multilayer antireflective coating is configured such that the front and / or the rear main face of the optical article has, in reflexion,

[0032] - a predetermined mean light reflection factor in the visible region Rv which is lower than or equal to 1.5 %, said mean light reflection factor in the visible region Rv being as defined in the ISO 13666:1998 Standard and measured in accordance with the ISO 8980-4, under the standard illuminant D65 and an angle of incidence of 15°,

[0033] - a predetermined Chroma C*, as defined in the international colorimetric CIE L*a*b* under the standard illuminant D65, which is lower than or equal to 4 for any angle of incidence between 0° to 75°.

[0034] BRIEF DESCRIPTION OF THE DRAWING

[0035] For a more complete understanding of the description provided herein and the advantages thereof, reference is now made to the brief description below, taken in connection with the accompanying drawing and detailed description, wherein like reference numerals represent like parts.

[0036] FIG. 1 to FIG.7 show, respectively, the variation of the Chroma C* and of the saturation value, S*uv, in the international colorimetric system L*a*b* under the standard illuminant D65 as function of the angle of incidence 0° to 75° for ophthalmic lenses 1 to 7 obtained from examples 1 to 7 according to the invention;

[0037] FIG.8 to FIG. 14 show, respectively, the variation of the Chroma C* and of the saturation value, S*uv, in the international colorimetric system L*a*b* under the illuminant LED 2700K as function of the angle of incidence 0° to 75° for ophthalmic lenses 1 to 7 obtained from examples 1 to 7 according to the invention.

[0038] FIG.15 shows the saturation value, S*uv in the international colorimetric system L*a*b* under the standard illuminant D65 as function of Rv, at an angle of incidence of 15° for ophthalmic lenses 1 to 7 obtained from examples 1 to 7 according to the invention;

[0039] FIG.16 shows the saturation value, S*uv in the international colorimetric system L*a*b* under the illuminant LED 2700K as function of Rv, at an angle of incidence of 15° for ophthalmic lenses 1 to 7 obtained from examples 1 to 7 according to the invention; and

[0040] FIG. 17 and 18 show, respectively, the variation of the Chroma C* in the international colorimetric system L*a*b* under the standard illuminant D65 as function of the angle of incidence 0° to 75° for ophthalmic lenses 8 and 9 obtained from examples 8 and 9 according to the invention.

[0041] DETAILED DESCRIPTION OF THE INVENTION

[0042] A) Definitions

[0043] The terms “comprise” (and any grammatical variation thereof, such as “comprises” and “comprising”), “have” (and any grammatical variation thereof, such as “has” and “having”), “contain” (and any grammatical variation thereof, such as “contains” and “containing”), and “include” (and any grammatical variation thereof, such as “includes” and “including”) are open- ended linking verbs. They are used to specify the presence of stated features, integers, steps or components or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps or components or groups thereof. As a result, a method, or a step in a method, that “comprises,” “has,” “contains,” or “includes” one or more steps or elements possesses those one or more steps or elements, but is not limited to possessing only those one or more steps or elements.

[0044] Unless otherwise indicated, all numbers or expressions referring to quantities of ingredients, ranges, reaction conditions, etc. used herein are to be understood as modified in all instances by the term "about."

[0045] Also, unless otherwise indicated, the indication of an interval of values « from X to Y » or “between X to Y”, according to the present invention, means as including the values of X and Y.

[0046] We mean an ophthalmic article defined by, but not exclusive of corrective lenses, noncorrective lenses, contact lenses, intra-ocular lenses, magnifying lenses, protective lenses, and visors containing photochromic compounds within a coating, the lens material, a film, or any adjacent layer.

[0047] As used herein, “a base element” can consist in an optical, such as an ophthalmic, substrate or in a support film of optical quality to be fixed on an optical / ophthalmic substrate thanks to an adhesive such as a pressure-sensitive adhesive of optical quality (PSA layer) (i.e.: laminate).

[0048] As used herein, “antireflective coating” means a coating, generally composed of antireflective thin layers and comprises at least one layer having a low refractive index which is lower than 1 .55, defined as “LI layer”, and at least one layer having a high refractive index which is equal to or higher than 1.55, defined as “HI layer.

[0049] In the present application, when an optical lens comprises one or more coatings onto the surface thereof, the expression "to deposit a layer, a sheet or a coating onto the article" is intended to mean that a layer, a sheet or a coating is deposited onto the external (exposed) surface of the outer coating of the article, that is to say its coating that is the most distant from the substrate.

[0050] Unless otherwise indicated, a coating, a layer or a sheet, that is said to be "on" a substrate / base element or deposited "onto" a substrate / base element” is defined as a coating, a layer or a sheet, which (i) is positioned above the substrate / base element, (ii) is not necessarily in contact with the substrate / base element, that is to say one or more intermediate coati ngs / sheets may be arranged between the substrate / base element and the coating or sheet in question, and (iii) does not necessarily completely cover the substrate / base element.

[0051] In a preferred embodiment, the coating on a substrate / base element or deposited onto a substrate / base element is in direct contact with this substrate.

[0052] When "a layer / sheet 1 is lying under a layer 2 / sheet 2", it is intended to mean that layer / sheet 2 is more distant from the substrate than layer 1 / sheet 1 respectively.

[0053] By outermost layer or sheet of the antireflective coating, it is meant the layer or sheet of the antireflective coating which is the furthest from the substrate.

[0054] By innermost layer or sheet of the antireflective coating, it is meant the layer or sheet of the antireflective coating which is the closest to the substrate or in the innermost position among all the layers / sheets of the antireflective coating. By inner layer / sheet of the antireflective coating, it is meant any layer / sheet of the antireflective coating except for the outermost layer / sheet of said antireflective coating.

[0055] Also, unless stated otherwise, all thicknesses disclosed in the present application relate to physical thicknesses.

[0056] As used herein, a layer of the antireflective coating is defined as having a thickness higher than or equal to 1 nm. Thus, any layer having a thickness lower than 1 nm will not be considered when counting the number of layers in the reflective coating.

[0057] In general, a sub-layer (having generally a physical thickness of 150 nm) is also not considered when counting the number of layers of the antireflective coating.

[0058] Unless otherwise specified, the refractive indexes referred to in the present application are expressed at 25 °C at a wavelength of 550 nm.

[0059] As used herein, the rear (or the inner or Concave or CC) face of the base element / substrate is intended to mean the face which, when using the article, is the nearest from the wearer’s eye. It is generally a concave face. On the contrary, the front face of the substrate / base element (or Convex or CX), is the face which, when using the article, is the most distant from the wearer’s eye. It is generally a convex face.

[0060] Also, as used herein, a “transparent substrate / base element” is understood to be transparent, when the observation of an image through said substrate is perceived with no significant loss of contrast, that is, when the formation of an image through said substrate is obtained without adversely affecting the quality of the image.

[0061] The colorimetric coefficients of the optical article of the invention in the international colorimetric system CIE L*a*b* (1976) (such as the Chroma C* and the hue “h”) are calculated between 380 and 780 nm and the observer into account (angle of 10°). The observer is a “standard observer” as defined in the international colorimetric system CIE L*a*b*. Indeed, in the CIE L*a*b* space, it is possible to express not only overall variations in color, but also in relation to one or more of the parameters L*, a* and b*. This can be used to define new parameters and to relate them to the attributes of the visual sensation. Clarity, related to luminosity, is directly represented by the value of L*. Chroma: C* = (a*2+ b*2)1 / 2defines the chromaticness. The angle of hue: h = tg-1 (b* / a*) (expressed in degrees) relates to the hue.

[0062] Also, unless otherwise indicated, the colorimetric coefficients of the optical article of the invention in the international colorimetric system CIE L*a*b* (1976) (such as the Chroma C*, S*uv, L*, a*, b* and h) are measured under the standard llluminant D65. However, some examples have also been done with the illuminant LED2700K.

[0063] According to the invention, the optical and colorimetric measurements (in reflection) of the at least one face coated with the antireflective multilayered coating of the invention were carried out with a Zeiss spectrophotometer and the standard observer 10°. They are provided for angles of incidence within the range from 0° to 75°.

[0064] According to the present disclosure, the saturation value S*uv is defined in the CIE 1976 L*, u*, v* color space, commonly known by its abbreviation CIELUV, which is a color space adopted by the International Commission on Illumination (CIE) in 1976 using . This CIELLIV color space is dedicated to determining the color of light and light sources, such as electronic screens. It uses another set of three colorimetric coordinates (L*, u*, v*), wherein L* is the lightness (luminance) and u* and v* represent the colors of a light or light source perceived by human vision. The colorimetric coordinates (L*, u*, v*) in the CIELLIV color space can be transformed as follows into a Chroma C*v= (u2+ v2) and a saturation 5" = S*v= C*v / L* . It is outlined that the saturation S* in the CIELLIV color space has no equivalent in the L*a*b* color space. In general, S*uv is measured at an angle of incidence of 15°.

[0065] According to the invention, the “angle of incidence (symbol 0)" is the angle formed by a ray light incident on an ophthalmic lens surface and a normal to the surface at the point of incidence. The ray light is for instance an illuminant light source, such as the standard illuminant D65 as defined in the international colorimetric CIE L*a*b* (1976). Generally, the angle of incidence changes from 0° (normal incidence) to 90° (grazing incidence). The usual range for angle of incidence is from 0° to 75°.

[0066] The optical characteristics comprise at least the mean light reflection factor in the visible region Rv, also named the "luminous reflectance".

[0067] Herein, the "luminous reflectance" noted Rv, is such as defined in the ISO 13666:1998 Standard, and measured in accordance with the ISO 8980-4:2006, i.e., this is the weighted spectral reflection average over the whole visible spectrum between 380 and 780 nm. Rvis usually measured for an angle of incidence lower than 17°, typically of 15°, but can be evaluated for any angle of incidence (here, from 0° to 75°).

[0068] The mean light reflection factor Rv may be defined by the following equation: where R(A) is the reflectance at a wavelength A, V(A) is the eye sensitivity function in the color space defined by the CIE (Commission on Illumination, in French “Commission Internationale de I’Eclairage”) in 1931 and D65(A) is the daylight illuminant defined in the CIE S005 / E-1998 standard.

[0069] The illuminant can be adapted according to the light situation. For instance, a derived Rv function may be defined for indoor light situations using LED illuminant rather than the usual D65.

[0070] According to the invention, when the mean light reflection factor in the visible region Rv onto the front and / or rear main face of the optical article is equal to or lower than 2.5%, this means that the multilayered antireflective coating is able to provide an antireflective behaviour onto the front and / or rear main surface of the optical article respectively.

[0071] As used herein, the factor Tv should be understood as defined by the international normalized definition (ISO 13666:1998 Standard) and is measured in accordance with the ISO 8980-3 Standard. It is defined in the wavelength range of from 380 to 780 nm. The optical characteristics may also comprise at least a mean reflection factor in the UV bands: UVA band ranges from 315 to 380nm and / or the UVB band ranges from 280 to 315 nm. These UVA and UVB bands are indeed particularly harmful to the retina. The mean reflection in the UVA and UVB regions may thus attain high levels (up to 60%) for traditional antireflective lenses.

[0072] According to the invention, a mean reflection factor Ruv is defined through the following relation: wherein R(A) represents the optical article spectral reflection factor at a given wavelength, and W(A) represents a weighting function equal to the product of the solar spectrum irradiance Es(A) and the efficiency relative spectral function S(A).

[0073] The spectral function W(A), enabling to calculate the ultraviolet radiation transmission factors, is defined according to the ISO 13666:1998 standard. It makes it possible to express the ultraviolet solar radiation distribution tempered by the relative spectral efficiency of such radiation for a user, since it simultaneously takes both the solar spectral energy Es(A) into account, which does globally emit less UVB-rays as compared to UVA-rays, and the spectral efficiency S(A), UVB-rays being more harmful than UVA-rays. The values for those three functions in the ultraviolet region are given in the table disclosed in ISO 13666:1998 standard (which is reproduced at page 6 of the publication WO 2012 / 076714).

[0074] The mean reflection factor Ruv is measured in the present application at an angle of incidence of 35°.

[0075] B) Optical article according to the invention

[0076] As mentioned-above, the Applicant has developed a transparent optical article, especially an ophthalmic lens such as spectacle lens, comprising a base element, such as a substrate in mineral or organic glass comprising at least an antireflective multilayered coating, which is able to and / or configured to appear almost non-visible for both wearer and observers, and to do so without compromising not only the mechanical performances of the optical article, its robustness, but also the economic and / or industrial feasibility of its manufacture.

[0077] The optical article according to the invention has a front main face and a rear main face, said optical article comprises: at least one base element having a front main surface and a rear main surface, at least one multilayer antireflective coating, deposited on said front main surface and / or said rear main surface of the base substrate, which comprises at least two layers having a low refractive index which is lower than 1.55, defined as “LI layer”, and at least two layers having a high refractive index which is equal to or higher than 1.55, defined as “HI layer”, characterized in that the at least one multilayer antireflective coating is configured such that the front and / or the rear main face of the optical article has, in reflexion, - a predetermined mean light reflection factor in the visible region Rv which is lower than or equal to 1.5 %, said mean light reflection factor in the visible region Rv being as defined in the ISO 13666:1998 Standard and measured in accordance with the ISO 8980-4, under the standard illuminant D65 and an angle of incidence of 15°,

[0078] - a predetermined Chroma C*, as defined in the international colorimetric CIE L*a*b* under the standard illuminant D65, which is lower than or equal to 4, preferably lower than or equal to 3, more preferably lower than or equal to 2.5 for any angle of incidence between 0° to 75° (i.e.: for all angles between 0° to 75°).

[0079] The structure of the base element will be described hereafter.

[0080] B.1 The base element / substrate

[0081] As mentioned above, the optical article comprises a base element having a front main surface and a rear main surface and at least one interferential multilayered coating deposited onto the front main surface and / or the rear main surface of said base element.

[0082] According to one embodiment, this base element can be a laminate, that is to say a support film of optical quality to be fixed on an optical / ophthalmic substrate thanks to an adhesive such as a pressure-sensitive adhesive of optical quality (PSA layer). Preferably, the support film is made of cellulose triacetate (TAC) and has a thickness of at least 40 microns, preferably a thickness in the range of 40 pm to 300 pm inclusive and preferably a thickness of 80 to 190 pm. Materials of the support film may be selected from the group of films made of cellulose triacetate (TAC), cellulose acetate butyrate (CAB), polycarbonate (PC), poly(ethylene terephthalate) (PET), poly(methylmethacrylate) (PMMA), urethane polymer (TPU), cyclo olefin copolymer (COC), polyester copoblock amide (like Pebax) and Polyimides.

[0083] According to another embodiment (described hereafter), the base element can consist in an ophthalmic substrate of a transparent optical article, such as a lens or lens blank, and more preferably an ophthalmic lens or lens blank.

[0084] Generally speaking, the interferential coating of the optical article according to the invention may be deposited onto any substrate, and preferably onto organic lens substrates, for example a thermoplastic or thermosetting plastic material.

[0085] Thermoplastic may be selected from, for instance: polyamides; polyimide; polysulfones; polycarbonates and copolymers thereof; poly(ethylene terephthalate) and polymethylmethacrylate (PMMA).

[0086] Thermoset materials may be selected from, for instance: cycloolefin copolymers such as ethylene / norbornene or ethylene / cyclopentadiene copolymers ; homo- and copolymers of allyl carbonates of linear or branched aliphatic or aromatic polyols, such as homopolymers of diethylene glycol bis(allyl carbonate) (CR 39®) ; homo- and copolymers of (meth)acrylic acid and esters thereof, which may be derived from bisphenol A ; polymer and copolymer of thio(meth)acrylic acid and esters thereof, polymer and copolymer of allyl esters which may be derived from Bisphenol A or phthalic acids and allyl aromatics such as styrene, polymer and copolymer of urethane and thiourethane, polymer and copolymer of epoxy, and polymer and copolymer of sulphide, disulfide and episulfide, and combinations thereof.

[0087] As used herein, a (co)polymer is intended to mean a copolymer or a polymer. As used herein, a (meth)acrylate is intended to mean an acrylate or a methacrylate. As used herein, a polycarbonate (PC) is intended to mean either homopolycarbonates or copolycarbonates and block copolycarbonates.

[0088] Homopolymers of diethylene glycol bis(allyl carbonate) (CR 39®), allylic and (meth)acrylic copolymers, having a refractive index between 1.54 and 1.58, polymer and copolymer of thiourethane, polycarbonates are preferred.

[0089] In particular, the base element recommended for the invention is a substrate selected from materials obtained by (co)polymerization of di(ethylene glycol) bis(allyl carbonate) and may correspond to the CR-39® ESSI LOR ORMA® lenses.

[0090] As it will be shown hereafter, the substrate / base element may be coated with one or more functional coatings prior to depositing the anti reflective coating of the invention. These functional coatings traditionally used in optics may be, without limitation, an impact-resistant primer layer, an abrasion-resistant coating and / or a scratch-resistant coating, a polarizing coating, a photochromic coating or a tinted coating. In the following a substrate means either a bare substrate or such a coated substrate.

[0091] Preferably, the substrate / base element and the optional abrasion-resistant coating and / or a scratch-resistant coating generally coated onto said substrate have a similar / close refractive index so as to avoid fringes or cosmetic defects.

[0092] Prior to depositing the interferential coating, the surface of said substrate is usually submitted to a physical or chemical surface activating treatment, so as to reinforce the adhesion of the antireflective coating. Such pre-treatment is generally conducted under vacuum. It may be a bombardment with energetic and / or reactive species, for example with an ion beam (“Ion PreCleaning” or “I PC”) or with an electron beam, a corona discharge treatment, an ion spallation treatment, an ultraviolet treatment or a plasma-mediated treatment under vacuum, generally using an oxygen or an argon plasma. It may also be an acid or basic treatment and / or a solventbased treatment (water, hydrogen peroxide or any organic solvent).

[0093] B.2 The multilayered antireflective coating

[0094] As previously mentioned, the antireflective coating according to the invention is first characterized to provide to the front main and / or the rear main face of the optical article a very low mean light reflection factor in the visible region, Rv (by using a standard illuminant D65).

[0095] Indeed, the at least one multilayer antireflective coating is configured such that the front and / or the rear main face of the optical article has, in reflexion, a predetermined mean light reflection factor in the visible region Rv which is lower than or equal to 1.5 %. Hence, this means that Rv on the front main face (defined as Rv(front)) and / or Rv on the rear main face (defined as Rv(rear)) is lower than or equal to 1.5 %. In addition, generally, the average of Rv(front) and Rv(rear) is also lower than or equal to 1.5 %. In general, the predetermined mean light reflection factor in the visible region Rv is lower than or equal to 1.0%, preferably lower than or equal to lower than or equal to 0.9%, in particular lower than or equal to 0.8%, such as lower than or equal to 0.7%, for an angle of incidence of 15° (standard illuminant D65).

[0096] Moreover, the at least one multilayer antireflective coating has itself a mean light reflection factor in the visible region Rv which is lower than or equal to 1 .5 %.

[0097] As used herein, “Rv lower than or equal to 1.5 %” for an angle of incidence of 15° includes the following values (in %) and / or any intervals comprised between these values: 1.5; 1.4; 1.3; 1.2; 1.1 ; 1.0; 0.9; 0.8; 0.7; 0.6; 0.5; 0.4; 0.3; 0.2; etc. For instance, Rv may be within the range from 0.1% to 1.5%, preferably from 0.2% to 1.5%.

[0098] In addition, the at least antireflective coating according to the invention is configured such that said front and / or the rear main surface of the optical article has also generally a very low reflexion for all wavelengths ranging from 400 to 700 nm.

[0099] Hence, the at least one multilayer antireflective coating may be also configured to provide on the front main face and / or and the rear main face of the optical article, in reflection (angle of incidence of 15°), a predetermined mean reflection factor for all wavelengths ranging from 400 nm to 700 nm, noted Rm400-700, which is lower than or equal to 1.5%, preferably lower than or equal to 1 .2%, preferably lower than or equal to 1 .0%, in particular lower than or equal to 0.8%. Also, here, this means that Rm400-700on the front main face (defined as Rm400-700(front)) and / or m4oo-7ooon t|ie rear majnface(definec|asRm400-700 (rear)) is lower than or equal to 1.5 %. In addition, generally, the average of Rm400-700(front) and Rm400-700(rear) is also lower than or equal to 1.5 %.

[0100] Generally, the at least one multilayer antireflective coating has itself in reflection (angle of incidence of 15°), a predetermined mean reflection factor for all wavelengths ranging from 400 nm to 700 nm, noted Rm400-700, which is lower than or equal to 1.5%, preferably lower than or equal to 1.2%, more preferably lower than or equal to 1.0%, in particular lower than or equal to 0.8%.

[0101] As used herein, “Rm400-700lower than or equal to 1.5 %” for an angle of incidence of 15° includes the following values (in %) and / or any intervals comprised between these values: 1.5; 1.4; 1.3; 1.2; 1.1 ; 1.0; 0.9; 0.8; 0.7; 0.6; 0.5; 0.4; 0.3; 0.2, etc.

[0102] Especially, the at least antireflective coating according to the invention is configured such that said front and / or the rear main surface of the optical article has also generally a low minimum mean light reflection factor (i.e.: minimum value) in the visible region.

[0103] Indeed, generally, the at least one multilayer antireflective coating may be also configured to provide on the front main face and / or and the rear main face of the optical article, in reflection, a minimum mean light reflection factor (i.e.: minimum value) in the visible region, noted Rvmin, for an angle of incidence 0min ranging from 0° to 75° which is lower than or equal to 1 %, preferably lower than or equal to 0.9%, in particular lower than or equal to 0.8%, especially lower than or equal to 0.7%. Hence, this means that Rvmin on the front main face (defined as Rvmin (front)) and / or Rvmin on the rear main face (defined as Rvmin (rear)) is lower than or equal to 1%, preferably lower than or equal to 0.9%, in particular lower than or equal to 0.8%, especially lower than or equal to 0.7%. In addition, generally, the average of Rvmin (front) and Rvmin (rear) is also lower than or equal to 1 %, preferably lower than or equal to 0.9%, in particular lower than or equal to 0.8%, especially lower than or equal to 0.7%.

[0104] Also, the at least one multilayer antireflective coating may have itself, in reflection, a minimum mean light reflection factor (i.e.: minimum value) in the visible region, noted Rvmin, for an angle of incidence 0min ranging from 0° to 75° which is lower than or equal to 1 %, preferably lower than or equal to 0.9%, in particular lower than or equal to 0.8%, especially lower than or equal to 0.7%.

[0105] According to the invention, “Rvmin lower than or equal to 1%” includes the following values (in %) and / or any intervals comprised between these values: 1.0; 0.95; 0.90; 0.85; 0.80; 0.75; 0.70; 0.65; 0.60; 0.55; 0.50; 0.45; 0.40; 0.35; 0.30; 0.25, etc. In general, Rmin is obtained at a low angle of incidence, such as 0°, 5°, 10° or 15°.

[0106] According to a characteristic of the invention, the multilayer antireflective coating has or is configured to provide to the front main face and / or the rear main face of the optical article, a ratio Rmin / Rv(i5°) s 1 .0, preferably within the range from 0.85 to 1 .0, Rv(is°) being the mean light reflection factor for an angle of incidence 0 of 15°.

[0107] According to another characteristic of the invention, the multilayer antireflective coating has or is configured to provide to the front main face and / or the rear main face of the optical article a ratio Rvmin / Rv(2o°) 1.0, preferably is within the range from 0.85 to 1 , Rv(2o") being the mean light reflection factor for an angle of incidence 0 of 20°.

[0108] Also, as used herein “a ratio Rvmin / Rv(is°) s 1.0” or “Rvmin / Rv(2o°) 1 .0” includes the following values and / or any intervals comprised between these values: 1.0; 0.99; 0.98; 0.97; 0.96; 0.95; 0.94; 0.93; 0.92; 0.91 ; 0.90; 0.89; 0.88; 0.87; 0.86; 0.85; 0.84; 0.83; 0.82; 0.81 ; 0.80; 0.79.

[0109] This means that the multilayer antireflective coating has the advantage to globally present a constant and low reflectance in the visible region and this whatever the angles of incidence.

[0110] Furthermore, the same optical characteristics are also obtained by using another illuminant, such as a LED2700K, that is to say, with this illuminant LED2700K, the at least AR coating has and / or is configured to provide to the front main face and / or the rear main face of the optical article in general:

[0111] - a mean light reflection factor in the visible region Rv is lower than or equal to 1.0%, preferably lower than or equal to lower than or equal to 0.9%, in particular lower than or equal to 0.8%, such as lower than or equal to 0.7%, for an angle of incidence of 15°;

[0112] - a Rm400'700, which is lower than or equal to 1.5 %, preferably lower than or equal to 1.2%, more preferably lower than or equal to 1.0%, in particular lower than or equal to 0.8%;

[0113] - a Rvmin, for an angle of incidence 0min ranging from 0° to 75°, which is lower than or equal to 1%, preferably lower than or equal to 0.9%, in particular lower than or equal to 0.8%, especially lower than or equal to 0.7%; - a ratio Rmin / Rv(is°) s 1.0, preferably within the range from 0.85 to 1.0, Rv(is°) being the mean light reflection factor for an angle of incidence 0 of 15°;

[0114] - a ratio Rvmin / Rv(2o°) 1.0, preferably is within the range from 0.85 to 1.

[0115] Generally, the AR coating may have and is configured to provide to the front main face and / or the rear main face of the optical article also very good antireflective characteristics in the UV bands. Generally, this kind of AR coating may therefore be placed on the rear main face of the optical article so as to protect the eyes of the wearer from light rays that may reflect onto the lens rear face and reach the wearer’s eye at a narrow incidence angle range, ranging from 30° to 45° (oblique incidence).

[0116] Hence, the AR coating may have and / or is configured to provide to the front main face and / or the rear main face, preferably the rear main face, of the optical article , in reflection, a mean reflection factor Ruv between 280 nm and 380 nm, weighted by the function W(A) defined in the ISO 13666:1998 standard, lower than or equal to 5%, preferably lower than or equal to 4%, and typically lower than or equal to 3%, for an angle of incidence (0) of 35°. As used herein “a Ruv < 5%” includes the following values and / or any intervals comprised between these values: 5.0; 4.5; 4.0; 3.5; 3.0; 2.5; etc.

[0117] Moreover, the AR coating according to the invention is also characterized by and / or is configured to provide to the front main face and / or the rear main face of the optical article improved colorimetric characteristics in reflexion and especially a very low Chroma C* at any angle of incidence. Indeed, the AR coating has and / or is configured to provide to the front main face and / or the rear main face of the optical article, in reflection, a Chroma C* which is lower than or equal to 4, preferably lower than or equal to 3, in particular lower than or equal to 2 and typically lower than or equal to 1.5 for any angle of incidence between 0° to 75° taking into account either the standard illuminant D65 or the illuminant LED2700K. Hence, this means that C* on the front main face (defined as C*(front)) and / or C* on the rear main face (defined as C*(rear)) is lower than or equal to 4, preferably lower than or equal to 3, in particular lower than or equal to 2 and typically lower than or equal to 1 .5 for any angle of incidence between 0° to 75° taking into account either the standard illuminant D65 or the illuminant LED2700K.

[0118] In general, whatever the illuminant, C* is lower than or equal to 3.0, preferably lower than or equal to 2 and typically lower than or equal to 1.5 for any angle of incidence between 0° to 75°. Preferably, C* is within the range from 0 to 3.5; more preferably from 0 to 3.0, especially from 0 to 2.5 and typically from 0 to 2.0, such as from 0 to 1.5. In general, C* is within the range from 0.08 to 2.0, preferably from 0.08 to 1 .5.

[0119] Here, “a C* < 4.0%” includes the following values and / or any intervals comprised between these values: 4.0; 3.9; 3.8; 3.7; 3.6; 3.5; 3.4; 3.3; 3.2; 3.1 ; 3.0; 2.9; 2.8; 2.7; 2.6; 2.5; 2.4; 2.3; 2.2; 2.1 ; 2.0; 1.9; 1.8; 1.7; 1.6; 1.5; 1.4; 1.3; 1.2; 1.1 ; 1.0; 0.9; 0.8; 0.7; 0.6; 0.5; 0.4; 0.3; 0.2; 0.1 ; 0.09; 0.08; 0.07; 0.06; 0.05; etc.

[0120] Therefore, even if the hue varies as function as the angle of incidence, since the Chroma C* is extremely low whatever the angle of incidence between 0° to 75°, the color change of the residual reflection of the AR coating or the color change on the front main face and / or on the rear main face of the optical article is not perceptible for an observer.

[0121] In particular, the AR coatings according to the invention have or is configured to provide to the front main face and / or the rear main face of the optical article, in reflection, also a very low saturation value, S*uv.

[0122] Generally, the at least one multilayer antireflective coating has and / or is configured such that said front and / or the rear main surface of the optical article has, in reflection, a S*uv which is lower than or equal to 0.5, preferably within the range from 0.01 to 0.50, more preferably within the range from 0.01 to 0.48, especially within the range from 0.01 to 0.47 and typically within the range from 0.01 to 0.45 for any angle of incidence between 0° to 75° (i.e.: for all angles within the range from 0° to 75°), said S*uv being as defined in the CIELLIV color space, under the standard illuminant D65 or the illuminant LED2700K. Hence, this means that S*uv on the front main face (defined as S*uv(front)) and / or S*uv on the rear main face (defined as S*uv(rear)) is lower than or equal to 0.5 for any angle of incidence between 0° to 75° under either the standard illuminant D65 or the illuminant LED2700K. In addition, generally, the average of S*uv(front) and S*uv(rear) is also lower than or equal to 0.5 for any angle of incidence between 0° to 75°.

[0123] Here, “a S*uv < 0.5” includes the following values and / or any intervals comprised between these values: 0.5; 0.49; 0.48; 0.47; 0.46; 0.45; 0.44; 0.43; 0.42; 0.41 ; 0.40; 0.39; 0.38; 0.37; 0.36; 0.35; 0.34; 0.33; 0.32; 0.31 ; 0.30; 0.29; 0.28; 0.27; 0.26; 0.25; 0.24; 0.23; 0.22; 0.21 ; 0.20; 0.15; 0.10; 0.09; 0.08; 0.07; 0.06; 0.05; 0.04; 0.03; 0.02; 0.01 ; etc.

[0124] Preferably, whatever the illuminant, the AR coating has or is configured such that said front and / or the rear main surface of the optical article has, in reflection, a saturation value, S*uv, which is lower than or equal to 0.4, preferably lower than or equal to 0.3 and typically lower than or equal to 0.3 for an angle of incidence of 15°.

[0125] Advantageously, the AR coating according to the invention has also or is configured such that said front and / or the rear main surface of the optical article, has in reflection specific colorimetric coefficients a* and b*, which are both close to 0.

[0126] Indeed, according to a characteristic of the invention, the AR coating has and / or is configured such that said front and / or the rear main surface of the optical article colorimetric has coefficients a* which falls within the range -3 < a* < 3, preferably within the range -2.0 < a* < 2.0 and typically within the range -1 < a* < 1.5 for all angles of incidence comprised between 0° and 75° and under the standard illuminant D65 or the illuminant LED2700K. Hence, this means that a* on the front main face (defined as a*(front)) and / or a* on the rear main face (defined as a*(rear)) falls within the range -3 < a*(front) and / or a*(rear) < 3, preferably within the range -2.0 < a*(front) and / or a*(rear) < 2.0 and typically within the range -1 < a*(front) and / or a*(rear) < 1.5 for all angles of incidence comprised between 0° and 75°.

[0127] According to another characteristic of the invention, the AR coating has and / or is configured such that said front and / or the rear main surface of the optical article, has in reflection colorimetric coefficients b* which falls within the range -3< b* < 3, preferably within the range - 2.0 < b* < 2.0 and typically within the range -1 .5 < b* < 1.5 for all angles of incidence comprised between 0° and 75° and under the standard illuminant D65 or the illuminant LED2700K. Hence, this means that b* on the front main face (defined as b*(front)) and / or b* on the rear main face (defined as b*(rear)) falls within the range -3< b*(front) and / or b*(rear) < 3, preferably within the range - 2.0 < b*(front) and / or b*(rear) < 2.0 and typically within the range -1.5 < b*(front) and / or b*(rear) < 1.5 for all angles of incidence comprised between 0° and 75°.

[0128] In general, when the at least one multilayer antireflective coating is coated on the front main surface of the base element, it is configured to provide on the front main face of the optical article one or more, preferably at least two, especially at least three, typically at least four, such as at least five of the above-mentioned optical characteristics: i.e.: Rv, Ruv, Rm400'700, Rvmin, Rvmin I RV(15°) and / or Rvmin / Rv<2o°). Generally, when the at least one multilayer antireflective coating is coated on the front main face of the base element, it is configured to provide on the front surface of the optical article all of the above-mentioned optical: Rv, Rm400'700, Rvmin, Rvmin / Rv(is°) and / or Rvmin / RV(2O°) and optionally Ruv (i.e.: front optical characteristics described above).

[0129] Preferably, when the at least one multilayer antireflective coating is coated on the front main surface of the base element, it is configured to provide on the front main face of the optical article one or more, preferably at least two, especially at least three, typically at least four (i.e.: all) of the above-mentioned colorimetric characteristics: i.e.: C*, a*, b*, S*uv (i.e.: front colorimetric characteristics described above).

[0130] In general, when the at least one multilayer antireflective coating is coated on the rear main surface of the base element, it is configured to provide on the rear main face of the optical article one or more, preferably at least two, especially at least three, typically at least four, such as at least five of the above-mentioned optical characteristics: i.e.: Rv, Ruv, Rm400'700, Rvmin, Rvmin I RV(15°) and / or Rvmin / Rv<2o°). Generally, when the at least one multilayer antireflective coating is coated on therear main surface of the base element, it is configured to provide on the rear face of the optical article all of the above-mentioned optical: Rv, Rm400'700, Rvmin, Rvmin / Rv(is°) and / or Rvmin / RV(2O°) and optionally Ruv (i.e.: rear optical characteristics described above).

[0131] Especially, when the at least one multilayer antireflective coating is coated on the rear main surface of the base element, it is configured to provide on the rear main face of the optical article one or more, preferably at least two, especially at least three, typically at least four (i.e.: all) of the above-mentioned colorimetric characteristics: i.e.: C*, a*, b*, S*uv (i.e.: rear colorimetric characteristics described above).

[0132] Especially, when the at least one multilayer antireflective coating is coated both on the front main surface and on the rear main surface of the base element (i.e.: two AR coatings according to the invention that may be similar or different), each AR coating is configured to provide on the rear main face and on the front face of the optical article one or more, preferably at least two, especially at least three, typically at least four, such as at least five of the above- mentioned optical characteristics: i.e.: Rv, Ruv, Rm400-700, Rvmin, Rvmin I Rv(15°) and / or Rvmin / Rv(20°) (average characteristics described above). Generally, when the two multilayer antireflective coatings are coated on the rear main surface and on the front main surface of the base element, each AR coating is configured to provide on the rear face and on the front main face of the optical article all of the above-mentioned optical: Rv, Rm400-700, Rvmin, Rvmin I Rv(15°) and / or Rvmin I Rv(20°) and optionally Ruv.

[0133] Preferably, when the at least one multilayer antireflective coating is coated both on the front main surface and on the rear main surface of the base element, each AR coating (that may be similar or different) is configured to provide on the front main face and on the rear main face of the optical article one or more, preferably at least two, especially at least three, typically at least four (i.e.: all) of the above-mentioned colorimetric characteristics: i.e.: C*, a*, b* (front characteristics described above), S*uv (average characteristic described above).

[0134] According to the invention, the aforementioned optical characteristics (Rv, C*, S*uv, Rv_(min) / Rv(2o°), etc.) of at least one multilayered antireflective coating, and their preferred ranges, can be combined. Due to reasons of conciseness, all these combinations cannot be described hereafter.

[0135] The structure of the at least AR coating according to the invention will now be described hereafter.

[0136] According to the invention, the at least AR coating according to the invention comprises at least two layers having a low refractive index which is lower than 1 .55, defined as “LI layer”, and at least two layers having a high refractive index which is equal to or higher than 1 .55, defined as “HI layer”. It is here a simple stack, since the layer total number in the interferential coating is higher than or equal to 4 and in general lower than or equal to 16.

[0137] According to an aspect of the invention, the total number of HI and LI layers in the AR coating is higher than or equal to 5, preferably higher than or equal to 6, more preferably higher than or equal to 7 and typically higher than or equal to 8.

[0138] According to another aspect of the invention, the total number of HI and LI layers in the AR coating is lower than or equal to 16, especially lower than or equal to 15, preferably lower than or equal to 14, more preferably lower than or equal to 13, and typically lower than or equal to 12, such as lower than or equal to 11 .

[0139] For instance, the total number of HI and LI layers in the AR coating ranges from 8 to 12 layers, preferably from 8 to 11.

[0140] HI layers and LI layers don't need to alternate with each other in the stack, although they also may, according to one embodiment of the invention. Two HI layers (or more) may be deposited onto each other, as well as two LI layers (or more) may be deposited onto each other. In the present application, when two HI layers (or more) are deposited onto each other, they are not considered as being a single HI layer when counting the number of layers of the interferential stack. The same applies to stacks of two or more adjacent LI layers.

[0141] In general, the HI layers and LI layers alternate with each other in the stack of the AR coating according to the invention. According to another aspect of the invention, the AR coating has a total physical thickness lower than or equal to 1 pm, in particular lower than or equal to 900 nm, preferably lower than or equal to 750 nm, typically lower than or equal to 600 nm, such as lower than or equal to 500 nm.

[0142] As used herein, “a thickness lower than or equal to 1 pm” includes the following values (in nm) and / or any intervals comprised between these values (limits included): 1000; 950; 900; 850; 800; 790; 780; 770; 760; 750; 740; 730; 720; 710; 700; 690; 680; 670; 660; 650; 640; 630; 620; 610; 600; 590; 580; 570; 560; 550; 540; 530; 520; 510; 500; 490; 480; 470; etc.

[0143] In particular, each HI layer of the AR coating has a physical thickness lower than or equal to 110 nm, preferably lower than or equal to 100 nm, more preferably lower than or equal to 90 nm and typically lower than or equal to 85 nm.

[0144] In general, the AR coating comprises successively (i.e: in direct contact), starting from the substrate:

[0145] (A) a first HI sheet, defined as “innermost HI sheet”, which preferably does not comprise any Ta2Os layer, and has in general a physical thickness lower than or equal to 50 nm, 40 nm, 30 nm, 25 nm, 20 nm, preferably lower than or equal to 15 nm;

[0146] (B) a first LI sheet, defined as “innermost LI sheet” and having in general a physical thickness lower than or equal to 80 nm, preferably lower than or equal to 70 nm and typically lower than or equal to 60 nm;

[0147] (C) a second HI sheet having in general a physical thickness lower than or equal to 60 nm, more preferably lower than or equal to 50 nm, 40 nm, 30 nm, 25 nm, 20 nm or 15 nm;

[0148] (D) a second LI layer, defined as “thick LI layer” which has a physical thickness higher than or equal to 50 nm, 60 nm, 70 nm, 100 nm or 110 nm, more preferably higher than or equal to 120 nm, more preferably higher than or equal to 130 nm and typically higher than or equal to 140 nm.

[0149] In general, the first HI sheet (A), having a refractive index higher than 1.55, does not comprise any Ta2Os layer and preferably does not comprise any Ta2Os-based layer.

[0150] Sheet (A) preferably comprises a ZrC>2 based layer, more preferably is a ZrCh-based layer. In one embodiment, sheet (A) comprises a ZrC>2 layer, more preferably is a ZrC>2 layer.

[0151] Sheet (A) preferably has a thickness higher than or equal to 4 nm, more preferably higher than or equal to 5 nm.

[0152] In one embodiment, sheet (A) comprises a high refractive index silicon-organic layer such as disclosed in WO 2017 / 021669, obtained by vacuum deposition, assisted by a source of ions, of at least one metal oxide and at least one organosilicon compound, such as octamethylcyclotetrasiloxane, decamethyltetrasiloxane, 2,4,6,8-tetramethylcyclotetrasiloxane, hexamethyldisiloxane, decamethylcyclopentasiloxane or dodecamethylpentasiloxane, said layer containing at least one metal oxide having a refractive index higher than or equal to 1.8, such as ZrO2.

[0153] In one embodiment, sheet (A) comprises two high refractive index layers in direct contact and its high refractive index layer in direct contact with the optionally coated substrate is an adhesion layer. Said adhesion layer may comprise a metal or metal oxide selected from chromium; sub-stoichiometric silicon oxide SiOx with 0.5<x<1.5, preferably 0.9<x<1.1 so as to have a refractive index larger than 1.55; and a mixture comprising chromium, silicon and oxygen, preferably chromium and silicon oxide(s) in which silicon oxides represent from 50 to 95 % by weight, preferably from 65 to 92 % by weight of said layer. Examples of commercially available materials that can be used to form said adhesion layer comprising chromium, silicon and oxygen are the materials Malbunit 8 / 1 (mixture of SiO2 and Cr) and Flexo (mixture of SiO and Cr), provided by the Umicore Materials AG company. In this embodiment, adhesion between sheet (A) and underlying optionally coated substrate is improved and delamination occurrence (adhesive failure) is decreased.

[0154] The second low refractive index sheet (B), having a refractive index of 1.55 or less, is in direct contact with sheet (A). Sheet (B) may comprise one single low refractive index layer or two low refractive index layers in direct contact. The layer(s) of sheet (B) generally comprise(s) one or more metal oxides, which can be chosen from the metal oxides described hereafter for the low refractive index layers of the AR coating.

[0155] Sheet (B) preferably comprises a SiCh-based layer, more preferably is a SiCh-based layer. In one embodiment, sheet (B) comprises a SiC>2 layer, more preferably is a SiC>2 layer.

[0156] In one embodiment, sheet (B) comprises a low refractive index silicon-organic layer such as disclosed in WO 2017 / 021669, obtained by vacuum deposition, assisted by a source of ions, of at least one organosilicon compound such as octamethylcyclotetrasiloxane, decamethyltetrasiloxane, 2,4,6,8-tetramethylcyclotetrasiloxane, hexamethyldisiloxane, decamethylcyclopentasiloxane or dodecamethylpentasiloxane.

[0157] Sheet (B) preferably has a thickness lower than or equal to 80 nm, more preferably lower than or equal to 75 nm or 70 nm. Sheet (B) preferably has a thickness higher than or equal to 20 nm, more preferably higher than or equal to 25 nm, 30 nm or 35 nm. Having a sufficiently thick sheet (B) enables to improve the abrasion resistance.

[0158] The thickness of sheet (B) is preferably lower than or equal to 60 nm or 55 nm when sheet (A) is in direct contact with an uncoated substrate having a refractive index of 1.55 or more or is in direct contact with a coating (typically an abrasion and / or scratch resistant coating) having a refractive index of 1.55 or more.

[0159] In one embodiment, the deposition of the layers of sheet (B) is performed in a vacuum chamber in which no supplementary gas is supplied during said deposition, which increases its density.

[0160] The third high refractive index sheet (C), having a refractive index higher than 1.55, is in direct contact with sheet (B). Sheet (C) may comprise one single high refractive index layer or two high refractive index layers in direct contact. The layer(s) of sheet (C) generally comprise(s) one or more metal oxides, which can be chosen from the metal oxides previously described for the high refractive index layers of the interferential coating, such as Ta2Os, Nb20s, PrTiCh, ZrC>2 and Y2O3. In one embodiment, sheet (C) does not comprise any Ta2Os layer, preferably any Ta2Os- based layer. In another embodiment, Ta2Os is present in a layer of sheet (C) in an amount of less than 80 % by weight, preferably less than 75 %, 50 %, 25 %, 10 %, 5 %, or 1 % by weight. In one embodiment, no layer of sheet (C) comprises Ta2Os.

[0161] Sheet (C) preferably comprises a ZrCh-based layer, more preferably is a ZrCh-based layer. In one embodiment, sheet (C) comprises a ZrC>2 layer, more preferably is a ZrC>2 layer.

[0162] Sheet (C) preferably has a thickness lower than or equal to 60 nm, more preferably lower than or equal to 50 nm, 40 nm, 30 nm, 25 nm, 20 nm or 15 nm. In one embodiment, these thickness requirements are simultaneously satisfied by sheets (A) and (C). Sheet (A) preferably has a thickness higher than or equal to 4 nm, more preferably higher than or equal to 5 nm, 7 nm or 10 nm.

[0163] In one embodiment, sheet (C) comprises a high refractive index silicon-organic layer such as disclosed in WO 2017 / 021669, obtained by vacuum deposition, assisted by a source of ions, of at least one metal oxide and at least one organosilicon compound, such as octamethylcyclotetrasiloxane, decamethyltetrasiloxane, 2,4,6,8-tetramethylcyclotetrasiloxane, hexamethyldisiloxane, decamethylcyclopentasiloxane or dodecamethylpentasiloxane, said layer containing at least one metal oxide having a refractive index higher than or equal to 1.8, such as ZrO2.

[0164] The total thickness of sheets (A), (B) and (C) preferably ranges from 40 to 100 nm, more preferably from 45 to 95 nm or from 50 to 90 nm.

[0165] The refractive indexes of sheets (A) and (C) can be independently chosen from the refractive indexes previously described for the high refractive index layers of the interferential coating. The refractive index of sheet (B) can be chosen from the refractive indexes previously described for the low refractive index layers of the interferential coating.

[0166] The total number of layers of the system of sheets (A) to (C) ranges from 3 to 6, more preferably from 3 to 4 or 5, and is ideally equal to three. In other words, sheets (A) and / or (B) and / or (C) are preferably monolayers. This system preferably comprises, in the direction moving away from the substrate, a ZrCh-based layer, a SiCh-based layer, and a ZrCh-based layer, more preferably consists of a ZrCh-based layer, a SiCh-based layer, and a ZrCh-based layer. This system preferably consists, in the direction moving away from the substrate, of a ZrC>2 layer, a SiC>2 layer, and a ZrC>2 layer, more preferably consists of a ZrC>2 layer, a SiC>2 layer, and a ZrC>2 layer.

[0167] The thick LI layer (D) is generally, starting from the substrate, the second LI layer among all the LI layers of the AR coating and enables to improve mechanical properties such as abrasion resistance and / or scratch resistance of the interferential coating and / or so as to reinforce its adhesion to the substrate or to the underlying coating.

[0168] The thick LI layer (D) has a thickness that is generally lower than or equal to any one of the following values: 600 nm, 500 nm, 450 nm, 400 nm, 375 nm, and that is generally higher than or equal to 50 nm, 60 nm, 70 nm, 100 nm or 110 nm, more preferably higher than or equal to 120, 130, 140, 150, 160 or 180 nm. Increasing the thickness of the thick LI layer (D) leads to an abrasion resistance improvement.

[0169] The thick LI layer (D) is preferably a SiCh-based layer, this layer comprising preferably at least 80 % by weight of silica, more preferably at least 90 % by weight of silica, relative to the layer total weight, and even more preferably consists of a silica layer. In another embodiment, this SiC>2-based layer is a silica layer doped with alumina, in amounts such as defined hereabove, preferably consists of a silica layer doped with alumina.

[0170] In the present invention, the thick LI layer (D) is deposited onto the system of three sheets (A), (B) and (C), deposited in this order onto the optionally coated substrate. These sheets / layer (A) to (D) belong to the AR coating according to the invention. Said thick LI layer (D) is in direct contact with sheet (C). This system (A) to (D) allows to improve abrasion resistance of the optical article without suffering from adhesion issues between the sub-layer and the underlying coating or the substrate.

[0171] These layers (A) to (D) may be deposited according to the method described in the document EP 3 884 315, paragraphs 0167-0171 (incorporated here by reference).

[0172] Generally, the outermost layer of the AR coating is a LI layer and has especially a physical thickness lower than or equal to 150 nm, preferably lower than or equal to 140 nm, more preferably lower than or equal to 120 nm and typically lower than or equal to 110 nm. This outermost LI layer has also preferably a physical thickness higher than or equal to 50 nm, more preferably higher than or equal to 60 nm and typically higher than or equal to 70 nm.

[0173] In addition, apart from this outermost LI layer and the thick LI layer, each LI layer of the AR coating, has in general a physical thickness lower than or equal to 90 nm, preferably lower than or equal to 80 nm, more preferably lower than or equal to 70 nm and typically lower than or equal to 60 nm. In addition, apart from this outermost LI layer and the thick LI layer, each LI layer of the AR coating, has in general a physical thickness higher than or equal to 8 nm, preferably higher than or equal to 10 nm and typically higher than or equal to 15 nm.

[0174] According to an embodiment, the AR coating comprises under the outermost LI layer or under, as it will be described below, a thin electrically conductive layer, a HI system composed of at least two HI layers, preferably of at least three LI layers (i.e.: here two or three LI layers were deposited one on another). As explained above, this HI system does not form a single HI layer when counting the number of layers of the interferential stack.

[0175] According to this embodiment, this HI system may include for instance, starting from the substrate, a first HI layer having a physical thickness within the range from 20 nm to 80 nm, preferably from 30 nm to 70 nm and typically from 40 nm to 60 nm and is generally composed of Ta2Os; a second HI layer having a physical thickness within the range from 5 nm to 50 nm, preferably from 8 nm to 40 nm and typically from 10 nm to 30 nm and is generally composed of ZrO2; a third HI layer having a physical thickness within the range from 5 nm to 50 nm, preferably from 10 nm to 300 nm and typically from 15 nm to 25 nm and is generally composed of Ta2Os.

[0176] It has been observed that this HI system, placed under the outermost LI layer or under the thin electrically conductive layer, enables to decrease the reflection in the UV band, especially at oblique angles of incidence. Therefore, the obtained AR coatings have very reflection in the UV band, Ruv, such as lower than or equal to 3%, preferably lower than or equal 2.5% for an angle of incidence of 35°.

[0177] In addition, according to an aspect of the invention, the ratio of the physical thickness of LI layers: physical thickness of HI layers is higher than or equal to 0.9, preferably higher than or equal to 1.0 and typically higher than or equal to 1.5, such as higher than or equal to 2.0. According to another aspect of the invention, the ratio of the physical thickness of LI layers: physical thickness of HI layers is lower than or equal to 5, preferably lower than or equal to 4.5.

[0178] This specific ratio enables also to improve the mechanical properties of the obtained AR coatings.

[0179] In general, the HI layers are conventional high-refractive-index layers, well known in the art. They generally contain one or more mineral oxides such as, in a non-limiting manner, zirconia (ZrCh), titanium oxide (TiCh), trititanium pentoxide (TiaOs), alumina (AI2O3), tantalum pentoxide (Ta2Os), neodymium oxide (Nd2Os), praseodymium oxide (P^Ch), praseodymium titanate (PrTiCh), La2C>3i, NbaOsi, or Y2O3. Optionally the high-index layers may also contain silica or other low-refractive-index materials, provided that their refractive index is higher than 1.6 as indicated above.

[0180] Preferably, the one or more HI layers are made of zirconia (ZrO2) and / or tantalum pentoxide (Ta2Os).

[0181] The LI layers are also well-known low-refractive-index layers and may comprise, in a nonlimiting manner: silicon oxide, or else a mixture of silica and alumina, in particular silica doped with alumina, the latter contributing to increase the thermal resistance of the UV-reflecting interference coating. Each LI layer is preferably a layer comprising at least 80% by weight silica and better still at least 90% by weight silica, relative to the total weight of the layer, and even better still consists of a silica layer.

[0182] Optionally, the low-index layers may also contain high-refractive-index materials, provided that the refractive index of the resulting layer is lower than 1.55.

[0183] When a LI layer comprising a mixture of SiO2 and AI2O3 is used, it preferably comprises from 1 % to 10% by weight, better still from 1% to 8% by weight and even better still from 1% to 5% by weight of AI2O3, with respect to the total weight of SiO2 + AI2O3 in this layer.

[0184] For example, SiO2 doped with 4% or less AI2O3 by weight, or SiO2 doped with 8% AI2O3 may be employed. Commercially available SiC>2 / AI2O3 mixtures may be used, such as the LIMA® mixture sold by Umicore Materials AG (refractive index comprised between n = 1.48-1.50 to 550 nm) or the substance L5® sold by Merck KGaA (refractive index n = 1.48 to 500 nm).

[0185] The outermost layer and the thick LI layer of the AR coating is in general a layer based on silica, preferably comprising at least 80% by weight silica and better still at least 90% by weight silica (for example a layer of silica doped with alumina) relative to the total weight of the layer, and even better still consists of a silica layer.

[0186] The optical article, such as an ophthalmic lens, of the invention may be made antistatic, i.e., such as to not retain and / or develop an appreciable electrostatic charge, by virtue of the incorporation of at least one electrically conductive layer into the stack present on the surface of the ophthalmic lens.

[0187] This electrically conductive layer is preferably located between two layers of the AR coating and / or is adjacent to a high-refractive-index layer of this AR coating. Preferably, the electrically conductive layer is located immediately under a low-refractive-index layer of the AR coating, typically the outermost LI layer, and hence forms ideally the penultimate layer of the AR coating.

[0188] The electrically conductive layer must be sufficiently thin not to decrease the transparency of the UV-reflecting interference coating. The electrically conductive layer is preferably made from an electrically conductive and highly transparent material, generally an optionally doped metal oxide. In this case, its thickness preferably ranges from 1 to 15 nm and more preferably from 1 to 10 nm. The electrically conductive layer preferably comprises an optionally doped metal oxide chosen from indium oxide, tin oxide, zinc oxide and their mixtures. Indium tin oxide (tin-doped indium oxide, ln2O3:Sn), aluminum-doped zinc oxide (ZnO:AI), indium oxide (I^Ch), and tin oxide (SnCh) are preferred. According to one optimal embodiment, the electrically conductive and optically transparent layer is a layer of indium tin oxide (ITO) or a layer of tin oxide.

[0189] Generally, the electrically conductive layer contributes, within the stack, but to a limited extent, because of its small thickness, to the obtainment of antireflection properties and forms a high-refractive-index layer in the UV-reflecting interference coating. This is the case for layers made from an electrically conductive and highly transparent material such as layers of ITO.

[0190] According to one embodiment of the invention, the AR coating comprises, in order starting from the substrate, which is optionally coated with one or more functional coatings,

[0191] (1) the first HI sheet (A), defined as “innermost HI sheet”, which preferably does not comprise any Ta2O5 layer, and has in general a physical thickness lower than or equal to 50 nm, 40 nm, 30 nm, 25 nm, 20 nm, preferably lower than or equal to 15 nm;

[0192] (2) the first LI sheet (B), defined as “innermost LI sheet” and having in general a physical thickness lower than or equal to 80 nm, preferably lower than or equal to 70 nm and typically lower than or equal to 60 nm;

[0193] (3) the second HI sheet (C) having in general a physical thickness lower than or equal to 60 nm, more preferably lower than or equal to 50 nm, 40 nm, 30 nm, 25 nm, 20 nm or 15 nm;

[0194] (4) the second LI layer (D), defined as “thick LI layer” which has a physical thickness higher than or equal to 50 nm, 60 nm, 70 nm, 100 nm or 110 nm, more preferably higher than or equal to 120 nm, more preferably higher than or equal to 130 nm and typically higher than or equal to 140 nm.; (5) a HI layer having a physical thickness lower than or equal to 55 nm, in particular ranging from 10 nm to 50 nm, preferably ranging from 15 nm to 40 nm, and typically ranging from 20 nm to 30 nm;

[0195] (6) a LI layer having a physical thickness lower than or equal to 70 nm, in particular ranging from 5 nm to 60 nm, preferably ranging from 10 nm to 50 nm, and typically ranging from 15 nm to 40 nm,

[0196] (7) a HI layer having a physical thickness lower than or equal to 130 nm, in particular ranging from 10 nm to 120 nm, preferably ranging from 20 nm to 110 nm, and typically ranging from 30 nm to 100 nm,

[0197] (8) optionally, an electrically conductive layer having a physical thickness lower than or equal to 10 nm, in particular ranging from 3 nm to 8 nm;

[0198] (9) the outermost LI layer having a physical thickness lower than or equal to 130 nm, in particular ranging from 60 nm to 120 nm, preferably ranging from 65 nm to 115 nm, and typically ranging from 70 nm to 110 nm.

[0199] According to another embodiment of the invention, the AR coating may comprise, in order starting from the substrate, which is optionally coated with one or more functional coatings,

[0200] (1) the first HI sheet, defined as “innermost HI sheet”, which preferably does not comprise any Ta2O5 layer, and has in general a physical thickness lower than or equal to 50 nm, 40 nm, 30 nm, 25 nm, 20 nm, preferably lower than or equal to 15 nm;

[0201] (2) the first LI sheet, defined as “innermost LI sheet” and having in general a physical thickness lower than or equal to 80 nm, preferably lower than or equal to 70 nm and typically lower than or equal to 60 nm;

[0202] (3) the second HI sheet having in general a physical thickness lower than or equal to 60 nm, more preferably lower than or equal to 50 nm, 40 nm, 30 nm, 25 nm, 20 nm or 15 nm;

[0203] (4) the second LI layer, defined as “thick LI layer” which has a physical thickness higher than or equal to 50 nm, 60 nm, 70 nm, 100 nm or 110 nm, more preferably higher than or equal to 120 nm, more preferably higher than or equal to 130 nm and typically higher than or equal to 140 nm;

[0204] (5) a HI layer having a physical thickness lower than or equal to 40 nm, in particular ranging from 8 nm to 30 nm, preferably ranging from 10 nm to 25 nm, and typically ranging from 15 nm to 20 nm;

[0205] (6) a LI layer having a physical thickness lower than or equal to 40 nm, in particular ranging from 8 nm to 33 nm, especially ranging from 8 nm to 30nm, preferably ranging from 10 nm to 25 nm, and typically ranging from 15 nm to 20 nm;

[0206] (7) the first HI layer of the HI sheet having a physical thickness within the range from 20 nm to 80 nm, preferably from 30 nm to 70 nm and typically from 40 nm to 60 nm and is generally composed of Ta2Os;

[0207] (9) the second HI layer of the HI sheet having a physical thickness within the range from 5 nm to 50 nm, preferably from 8 nm to 40 nm and typically from 10 nm to 30 nm and is generally composed of ZrCh;

[0208] (10) the third HI layer of the HI sheet having a physical thickness within the range from 5 nm to 50 nm, preferably from 10 nm to 40 nm, more preferably from 10 nm to 30 nm and typically from 15 nm to 25 nm and is generally composed of Ta2Os ;

[0209] (10) optionally, an electrically conductive layer having a physical thickness lower than or equal to 10 nm, in particular ranging from 3 nm to 8 nm;

[0210] (11) the outermost LI layer having a physical thickness lower than or equal to 130 nm, in particular ranging from 60 nm to 120 nm, preferably ranging from 65 nm to 115 nm, and typically ranging from 70 nm to 110 nm.

[0211] B.3 Other functional layers

[0212] The antireflective coating may be deposited directly onto a bare substrate.

[0213] In some applications, it is preferred that the main surface of the substrate be coated with one or more functional coatings improving its optical and / or mechanical properties, prior to depositing the antireflective coating of the invention.

[0214] These functional coatings traditionally used in optics may be, without limitation, an impactresistant primer layer, an abrasion- and / or scratch-resistant coating (hard coat), a hydrophobic and / or oleophobic coating, an antistatic coating especially on the concave face of the optical article, or a stack made of two or more of such coatings.

[0215] In addition, prior to depositing the AR coating according to the invention or other functional coatings, the surface of the article is usually submitted to a physical or chemical surface activating and cleaning pre-treatment, so as to improve the adhesion of the layer to be deposited, such as disclosed in WO 2013 / 013929. This pre-treatment is generally performed on the surface of an abrasion- and / or scratch-resistant coating (hard coat).

[0216] This pre-treatment is generally carried out under vacuum. It may be a bombardment with energetic species, for example an ion beam method ("Ion Pre-Cleaning" or "I PC") or an electron beam method, a corona treatment, an ion spallation treatment, an ultraviolet treatment or a plasma treatment under vacuum, using typically an oxygen or an argon plasma. It may also be an acid or a base surface treatment and / or a solvent surface treatment (using water or an organic solvent) with or without ultrasonic treatment. Many treatments may be combined. Thanks to these cleaning treatments, the cleanliness of the substrate surface is optimized.

[0217] By energetic species, it is meant species with an energy ranging from 1 to 300 eV, preferably from 1 to 150 eV, and more preferably from 10 to 150 eV and most preferably from 40 to 150 eV. Energetic species may be chemical species such as ions, radicals, or species such as photons or electrons.

[0218] Anti-abrasion and / or anti-scratch coating

[0219] The antireflective coating of the invention is preferably deposited onto an anti-abrasion and / or anti-scratch coating.

[0220] The anti-abrasion and / or scratch-resistant coating may be any layer traditionally used as an anti-abrasion and / or anti-scratch coating in the field of ophthalmic lenses. The anti-abrasion and / or scratch-resistant coatings are preferably hard coatings based on poly(meth)acrylates or silanes, generally comprising one or more mineral fillers intended to increase the hardness and / or the refractive index of the coating once cured. Hard anti-abrasion and / or scratch-resistant coatings are preferably prepared from compositions comprising at least one alkoxysilane and / or a hydrolyzate thereof, obtained for example through hydrolysis with a hydrochloric acid solution and optionally condensation and / or curing catalysts.

[0221] Suitable coatings, that are recommended for the present invention include coatings based on epoxysilane hydrolyzates such as those described in the patents FR 2 702 486 (EP 0 614 957), US 4 211 823 and US 5 015 523.

[0222] The anti-abrasion and / or scratch-resistant coating composition may be deposited onto the main face of the substrate by dip- or spin-coating. It is then cured by a suitable method (preferably using heat or ultraviolet radiation).

[0223] The thickness of the anti-abrasion and / or scratch-resistant coating does generally vary from 2 to 10 .m, preferably from 3 to 5 .m.

[0224] Primer coating

[0225] Prior to depositing the abrasion-resistant coating and / or the scratch-resistant coating, it is possible to apply onto the substrate a primer coating to improve the impact resistance and / or the adhesion of the subsequent layers in the final product. This coating may be any impact-resistant primer layer traditionally used for articles in a transparent polymer material, such as ophthalmic lenses.

[0226] Preferred primer compositions are compositions based on polyurethanes and compositions based on latexes, especially polyurethane type latexes optionally containing polyester units.

[0227] Such primer compositions may be deposited onto the article faces by dip- or spin-coating, thereafter be dried at a temperature of at least 70 °C and up to 100 °C, preferably of about 90 °C, for a time period ranging from 2 minutes to 2 hours, generally of about 15 minutes, to form primer layers having thicknesses, after curing, of from 0,2 to 2,5 .m, preferably of from 0,5 to 1 ,5 .m.

[0228] Hydrophobic and / or oleophobic coating

[0229] The ophthalmic lens according to the invention may also comprise coatings formed on the antireflective coating and capable of modifying the surface properties thereof, such as hydrophobic and / or oleophobic coatings (antifouling topcoat). These coatings are preferably deposited onto the outer layer of the antireflective coating. As a rule, their thickness is lower than or equal to 10 nm, does preferably range from 1 to 10 nm, more preferably from 1 to 5 nm.

[0230] Instead of the hydrophobic coating, a hydrophilic coating may be used which provides antifog properties, or an antifog precursor coating which provides antifog properties when associated with a surfactant. Examples of such antifog precursor coatings are described in the patent application WO 2011 / 080472. Electrochromic

[0231] The optical article may comprise, generally directly deposited onto the AR coating according to the invention, an electrochromic stack, such as the one described in the document W02020 / 021107. By definition, an electrochromic stack is able to reversibly switch from an activated state when an electrical potential is applied to a deactivated state when the reverse electrical potential is applied.

[0232] For instance, this one is composed of at least five ceramic layers disposed successively on each other. Preferably, the electrochromic stack comprises a first and a second transparent conductive electrode layers (TCO layers), and the following layers placed between said first and a second transparent conductive electrode layers: one electrochromic layer (EC layer), one ion reservoir layer (IR layer) and one dielectric spacer layer (DS layer), said DS layer being placed between the EC layer and the IR layer.

[0233] Photochromic

[0234] Then, the optical article may comprise a photochromic stack, such as the one described in the document US 10 / 493486. In general, the photochromic stack is disposed below the AR coating.

[0235] Especially, a photochromic stack is coated on the rear main surface of the optical article and comprises at least one photochromic layer including at least one photochromic compound which is selected to be able to reversibly switch from a deactivated state corresponding to a bleached state to an activated state corresponding to a colored state when an electromagnetic radiation having a wavelength of greater than a predetermined wavelength is applied. This predetermined wavelength depends on generally of the transmission characteristics of the substrate.

[0236] Blue cut

[0237] Then, the optical article may comprise an absorbing dye and / or an interferential coating, filtering the blue-violet radiation, such as explained in the EP4297629 incorporated therein by reference). Characterizing the blue-violet radiation filtering performance of a lens, associated with long-term protection, is done by calculating a weighted average cut over the blue-violet radiation from 400 to 455 nm, which corresponds to the harmful part of blue radiation as defined in ISO TR20772:2018 and in several peer-reviewed papers (Marie et al., Cell Death and Disease, 2020), (Marie et al., Cell Death and Disease, 2018), (Arnault, Barrau et al., 2013): : or where T(A) : Transmittance (%)

[0238] B'(A) : Refined blue radiation hazard function defined in the peer-reviewed paper (Arnault et al., PlosOne, 2013) and consistent with the ISO definition of harmful blue radiation from 400 to 455 nm (ISO TR 20772:2018).

[0239] B(A) : Blue radiation hazard function (ISO 8980-3: Annex B), much broader than the refined B’, proposed in the 1970s by ICNIRP.

[0240] The way we calculate BVC and Tv are similar: for both, we weight the spectral transmittance of the lens by a biological function. For BVC, this is the blue hazard function for the retina B’ and for Tv, this is the photopic visual sensitivity function of the eye (V).

[0241] Beyond its impact on cumulative damage to the retina, blue radiation favors discomfort glare (Bullough, 2009) and may promote symptoms of visual fatigue, as it scatters more in the eye. In that sense, for short-term light protection, comfort is notably calculated by weighting the spectral transmittance of the lens over the whole blue range from 380 to 500nm with the spectral emission of a reference LED spectrum (CIE 015:2018) (Alexander Kokka et al 2018 Metrologia 55 526) representative of LED-based digital screens emission. The spectral range can be limited to 430- 470nm in some embodiments, or even from 440 to 460 nm, as the peak emission is around 450 nm.

[0242] Filtering in that range may also provide increased visual performance due to increased contrast sensitivity.

[0243] In order to quantify the cutting of short wavelengths i.e. blue light coming for example from car LED headlights, a parameter called the light cut factor CutLED can be used. CutLED is defined as follows:

[0244] Si* so (tens T% x LED emission%)

[0245] Cut LEI) = 100 -

[0246] XSw emission^ where Z is a discrete or continuous i.e. integral sum operator, A is the wavelength in nm, lens T% is the spectral transmittance of the lens in % and LED emission is the spectral distribution of a white light emitting diode. As the light cut factor is a weighted function of the light source, the exact type of light source is not relevant, as soon as the main emission peak of the light source is located in a range of wavelengths between 430 nm and 480 nm, in particular between 440 nm and 465 nm.

[0247] The calculated CutLED is also indicative of the capability of filtering the solar light as the solar spectrum also comprises a high level of emission in the 430 nm - 480 nm range.

[0248] LED emission is defined in% in the Cut LED formula above.

[0249] Typically, an optical article according to the invention comprises a substrate / base element that is successively coated on its front face and / or on its rear face with an impact-resistant primer layer, an anti-abrasion and scratch-resistant layer, the antireflective coating according to the invention, and with a hydrophobic and / or oleophobic coating or with a hydrophilic coating which provides antifog properties or an antifog precursor coating. The optical article according to the invention is preferably an ophthalmic lens for spectacles (spectacle lens), or a blank for ophthalmic lenses. The lens may be a polarized lens, a photochromic lens or a solar lens, which may be tinted or not, be corrective, or not.

[0250] Especially, the rear main face of the substrate of the optical article may be coated with the AR coating according to examples 5 and 6 which has a low Ruv at an angle of incidence of 35°.

[0251] In one embodiment, the optical article according to the invention does not absorb in the visible or not much, which means, in the context of the present application, that its transmission factor in the visible range TV, also called relative transmission factor in the visible range, is higher than 90%, more preferably higher than 95%, even more preferably higher than 96% and most preferably higher than 97% (i.e.: clear lens).

[0252] The factor V should be understood as defined by the international normalized definition (ISO 13666:1998 Standard) and is measured in accordance with the ISO 8980-3 Standard. It is defined in the wavelength range of from 380 to 780 nm.

[0253] Preferably, the light absorption of the article coated according to the invention is lower than or equal to 1%.

[0254] According to an embodiment, the optical article is a tinted optical article or a sunglass optical article including a dye and / or pigments, said tinted optical article or a sunglass optical article comprises one of the said at least one multilayered antireflective coating coated on the front main face and / or on the rear main surface of the base element.

[0255] Preferably, the optical article may be:

[0256] - a clear optical article having, in reflection, on its front main face and / or and on its rear main face, a transmission factor in the visible range Tv, which is higher than 90%, more preferably higher than 95%, even more preferably higher than 96% and most preferably higher than 97%, or

[0257] - a blue cut optical article comprising a selective filter blocking, at least partially, blue light in a wavelength range chosen within the 400- 460 nm range; or

[0258] - a photochromic optical article, or

[0259] - an electrochromic optical artcilar, which comprises two of the said at least one multilayered antireflective coatings coated respectively on the front main face and on the rear main face.

[0260] Generally, the optical article is an optical lens, especially an ophthalmic lens.

[0261] C) Process

[0262] The present invention may also relate to a process for manufacturing an optical article as defined in any one of the preceding claims, comprising the following steps:

[0263] (a) providing the base element having a front main surface and a rear main surface ;

[0264] (b) optionally, depositing successively onto front main surface and / or onto the rear main surface, a primer coating, an anti-abrasion and / or anti-scratch coating (also named hardcoat); (c) depositing on the anti-abrasion and / or anti-scratch coating, the AR coating according to the invention.

[0265] In general, the AR coating and the other layers of the optical article may be deposited by vapor phase deposition, under vacuum, in a vacuum deposition chamber, according to any of the following methods: i) by evaporation, optionally under ion beam assistance; ii) by ion-beam spraying; iii) by cathode sputtering; iv) by plasma-assisted chemical vapor deposition.

[0266] These various methods are described in the following references "Thin Film Processes" and "Thin Film Processes II," Vossen & Kern, Ed., Academic Press, 1978 and 1991 , respectively. A particularly recommended method is evaporation under vacuum. Preferably, the deposition of each of the above-mentioned layers is conducted by evaporation under vacuum. Such a process does advantageously avoid heating the substrate, which is particularly interesting for coating heat-sensitive substrates such as organic glasses.

[0267] In general, the AR coating and the other layers of the optical article are deposited by evaporation, optionally under ion beam assistance.

[0268] Naturally, the various embodiments described above for the optical article also apply to this method of manufacturing the optical article and will not be repeated below.

[0269] D) Eyewear device

[0270] The invention also relates to an eyewear device comprising at least one optical article as defined above and preferably an holding structure configured to hold the at least optical article facing a wearer’s eye.

[0271] Especially, the eyewear device comprises at least an optical article having a front main face and a rear main face, comprising: at least one base element having a front main surface and a rear main surface, at least one multilayer anti reflective coating, deposited on said front main surface and / or said rear main surface of the base substrate, which comprises at least two layers having a low refractive index which is lower than 1.55, defined as “LI layer”, and at least two layers having a high refractive index which is equal to or higher than 1.55, defined as “HI layer”, characterized in that the at least one multilayer antireflective coating is configured such that the front and / or the rear main surface of the optical article has, in reflexion,

[0272] - a predetermined mean light reflection factor in the visible region Rv which is lower than or equal to 1.5 %, said mean light reflection factor in the visible region Rv being as defined in the ISO 13666:1998 Standard and measured in accordance with the ISO 8980-4, under the standard illuminant D65 and an angle of incidence of 15°,

[0273] - a predetermined Chroma C*, as defined in the international colorimetric CIE L*a*b* under the standard illuminant D65, which is lower than or equal to 4 for any angle of incidence between 0° to 75°.

[0274] Naturally, the various embodiments described above for the optical article also apply to this eyewear device and will not be repeated below.

[0275] EXAMPLES

[0276] A) Characterization

[0277] Optical and colorimetric measurements (in reflection) of the surface of the base element (i.e.: substrate) coated on its front surface with the exemplified interferential multilayered coatings (front face) : mean reflection factors Rv, Ruv, hue angle h, chroma C*, S*uv in the international colorimetric CIE (L*, a*, b*) space were carried out with a spectrophotometer, taking into account the standard illuminant D65 or an illuminant LED2700K, and the standard observer 10° (for h and C*). They are provided for an angle of incidence (also named hereafter “AOI” or 0) within the range from 0° to 75° for forward reflection (Cx face) and 35° for backward reflection (Cc face).

[0278] B) Preparation of the optical articles

[0279] The ophthalmic lenses employed in the examples comprise an ESSI LOR ORMA® lens substrate 30 of 65 mm diameter, of refractive index of 1 .50, of -2.00 diopter power and of 1 .2 mm thickness, coated on its front and back faces successively with a primer layer and an anti-abrasion and anti-scratch coating (hard coat).

[0280] The primer coating, which has a refractive index of 1.6, was formed from a coating composition having a dry extract weight of 20 % and containing a polyurethane latex (LI5200 from Alberdingk Boley), a ZrC>2 based colloid (SZR-CWfrom Sakai Chemical Industry), deionized water and Coatosil 77 as a surfactant.

[0281] The anti-scratch coating (hard coat) has also a refractive index around 1.6 and is obtained by curing a composition comprising a hydrolyzate of glycol(gamma glycidoxypropyl trimethoxysilane), a composite colloid of TiCh / ZrC>2 / SiC>2 (TiC>2 being a major component). The hard coat thickness is 2.6 micrometers.

[0282] The layers of the antireflection coating were deposited without heating of the substrates by vacuum evaporation (evaporation source: the electron gun).

[0283] The method for forming the exemplified anti refl ection stack comprises a deposition step of a ZrO2layer (sheet (A)) at a rate of 1 nm / s under an O2 pressure of 7.0*1 O'5mBar, a deposition step of a SiC>2 layer (sheet (B)) at a rate of 2 nm / s, a deposition step of a ZrC>2 layer (sheet (C)) at a rate of 1 nm / s under an O2 pressure of 7.0*1 O'5mBar, a surface activation step of this ZrC>2 layer using an argon ion beam for 30 seconds (same treatment as I PC already conducted directly on the substrate), a deposition step of a SiC>2 sub-layer at a rate of 3 nm / s (at a pressure of 5*1 O'5mBar), a surface activation step of the sub-layer using an argon ion beam for 30 seconds (same treatment as IPC already conducted directly on the substrate), a deposition step of a HI layer (ZrC>2 or Ta2Os) at a rate of 2 nm / s, a deposition step of a LI layer (SiCh) at a rate of 2 nm / s, a deposition step of a HI layer (ZrC>2 or Ta2Os) at a rate of 2 nm / s, a deposition step of a thin electrically conductive layer (HI, ITO or SnO2) at a rate of 1 nm / s with an oxygen ion assistance (ion gun: 2 A, 120 V), a deposition step of a LI layer (SiCh) at a rate of 2-3 nm / s, and lastly a deposition step of an Optool DSX® layer at a rate of 0.4 nm / s.

[0284] Deposition step of HI layers of ZrO2 was done with a gas supply (O2, under a pressure of 7.5x10'5mBar). Deposition step of HI Layers of Ta2Os was done with an oxygen ion assistance (ion gun:

[0285] 3 A, 130 V) leading to a pressure of about 2x1 O'4mBar.

[0286] The deposition tool was a Satis 1200DLF machine equipped with a Temescal (8kV) electron gun for the evaporation of the oxides, and a (Veeco Mark II) ion gun for the preliminary phase of preparing the surface of the substrate with argon ions (I PC). The thickness of the layers was controlled by means of a quartz microbalance. The spectral measurements were carried out using a variable-incidence Perkin-Elmer lambda 850 spectrophotometer with a universal reflectance accessory (URA).

[0287] C) Tested Lenses and results

[0288] C.1 Structures The following structures have been exemplified:

[0289] Table 1

[0290] Table 2

[0291] C.2 Results

[0292] Table 3 below illustrates the value of Chroma C* for all the angles of incidence within the range from 0° to 75° for the examples 1 to 7 according to the invention (llluminant D65). Table 3

[0293] This table 3, as well as Fig.1 to 14 and Fig.17 and 18, show that the Chroma C* value is extremely low for all the exemplified lenses whatever the angle of incidence (from 0° to 75°) and whatever the used illuminant.

[0294] In addition, Fig.15 and Fig.16 also show that for the exemplified lenses 1 to 7, both the Chroma C* and the saturation value are very low. Especially, for the exemplified lenses 1 and 2, the Rv values are slightly higher than the ones of the exemplified lenses 3 to 7, while having a low S*uv. Hence, the exemplified lenses 1 and 2 have a little residual reflection, but this one appears clear (i.e.: transparent or white) for an observer, whereas the exemplified lenses 3 to 7 have no discernible residual reflection; in other word, the AR coating of these lenses is not visible for an observer. Table 4 below shows the different optical and colorimetric characteristics of the exemplified lens 1 (AR coating Ex.1 / illuminant D65):

[0295] Table 4

[0296] It can be seen from this table 4 that the minimum Rv (Rvmin) occurs at 0°, and RVm,n / Rl5"=0.97, RVmin / R20°=0.93. Table 5 below shows the different optical and colorimetric characteristics of the exemplified lens 2 (AR coating Ex.2 / illuminant D65):

[0297] Table 5

[0298] Table 5 shows that Rvmin occurs at 10°, and Rmin / R15°=1.00, Rmin / R20°=0.98 for lens 2.

[0299] Hence, reflectance of these two AR coatings Ex.1 and Ex.2 (respectively forming lenses 1 and 2) is always lower than 5% over a broad visible light region 400-780 nm. Their mean reflectance Rm (400-700 nm) is 0.74% (Ex-1 / Lens 1) and 0.77% (Ex-2 / Lens 2), respectively.

[0300] Tables 6 and 7 below show the different optical and colorimetric characteristics of the exemplified lens 3 (AR coating Ex.3 / illuminant D65) and exemplified lens 4 (AR coating Ex.4 / illuminant D65):

[0301] Table 6

[0302] Table 7

[0303] AR coating according to Ex.3 and Ex.4 (respectively lenses 3 and 4) have also a very low reflection Chroma (C*<1.5) over a broad range of incident angles ranging from 0° to 75°. At an angle of incidence <20°, their Rv values varies slightly (with the angle of incidence). For Ex-3 / Lens 3, Rvmin occurs at 5°, and Rvmin / R15°=0.97, Rvmin / R20°=0.89.

[0304] For Ex-4 / Lens 4, Rvmin occurs at 0°, and Rvmin / R15°=0.97, Rvmin / R20°=0.92.

[0305] In comparison with Ex-1 and Ex-2, reflection C* of Ex-3 and Ex-4 is a bit higher, but is still well controlled at a very low level, i.e. C*<1.5 over all the angled of incidence 0°-75°. However, Rv values of Ex-3 and Ex-4 are much lower than those of Ex-1 and Ex-2. Particularly, Rv of Ex-3 stack is very low, Rv<0.25% at an angle of incidence <20°, which leads to neutral color properties.

[0306] In addition, reflectance of these two stacks is always lower than 5% over a broad visible light region 390-780 nm. Their mean reflectance Rm (400-700 nm) is 0.40% (Ex-3) and 0.50% (Ex-4), respectively.

[0307] Tables 8 and 9 below show the different optical and colorimetric characteristics of the exemplified lens 5 (AR coating Ex.5 / illuminant D65) and exemplified lens 6 (AR coating Ex.6 / illuminant D65): Table 8

[0308] Table 9

[0309] The C* values of the AR coatings according to Ex.4 and Ex.6 are well-controlled <1.0 and <1 .5, respectively, over angle of incidence from 0°-75°. At 0 <20°, their Rv values varies slightly with 0. For both Ex-5 and Ex-6, Rvmin occurs at 0°. For Ex-5, Rvmin / R15°=0.94 and Rvmin / R20°=0.87. For Ex-6, Rvmin / R15°=0.95 and Rvmin / R20°=0.88. In addition, Ruv of these two AR stacks is very low for an angle of incidence of 35°, i.e.: < 2.25% (Ruv = 2.20% for the AR coatings according to Ex.5 and Ruv = 2.25% for the AR coatings according to Ex.6), which is suitable for Cc surface for high ESPF UV protection. Therefore, these two stacks combine neutral reflection color (achromatic), very low Rv and good UV protection.

[0310] In addition, it has been observed that the reflectance of these two stacks is always lower than 5% over the whole visible light region 380-780 nm. Their mean reflectance Rm (400-700 nm) is 0.51% (Ex-5) and 0.47% (Ex-6), respectively. Table 10 below shows the different optical and colorimetric characteristics of the exemplified lens 7 (AR coating Ex.7 / illuminant D65):

[0311] Table 10

[0312] Table 10 shows that the C* values of the AR coating according to Ex-7 is well-controlled <1.0 over 0 from 0°-75°. At 0<20°, Rv values of Ex-7 is very low (<0.31 %) and varies slightly with 0. Rvmin occurs at 0°, Rvmin / R15°=0.94 and Rvmin / R20°=0.86. Ex-7 combines neutral reflection color (achromatic) and very low Rv properties.

[0313] It has also been observed that reflectance of this stack is always lower than 5% over the whole visible light region 380-780 nm. Its mean reflectance Rm (400-700 nm) is 0.42%.

[0314] In addition, similar characteristics have been obtained for the exemplified lenses 1 to 7 when using the illuminant LED2700K.

[0315] Table 11 below shows the different optical characteristics Rv and Ruv of the exemplified lens 8 (AR coating Ex.8 / illuminant D65):

[0316] Table 11

[0317] In addition, Fig.17 shows the variation of the Chroma C* in the international colorimetric system L*a*b* under the standard illuminant D65 as function of the angle of incidence 0° to 75° for this ophthalmic Lens 8. The AR structure (AR Ex.8) of this Lens 8 is similar to the one of Lens 7 (AR Ex.7), except that the sequence of the two high index layers Ta2Os and ZrC>2 exchanged. C* of Lens-8 is well-controlled <1.0 over AOI from 0°-75°. At AOI<20°, Rv values of Lens 8 are lower than <0.47% and varies slightly with AOI. Rmin occurs at 0°, Rmin / Ri5°=0.97 and Rmin / R2o°=O.92. Rv of Lens 8 at AOI<20° is higher than that of Lens 7, but lower than that of Lens 1 wherein from L5 all the HI layers of the AR Ex.1 are made of Ta2Osand lower than that of Lens 2 wherein from L5 all the HI layers of the AR Ex.2 are made of ZrO2.The mean reflectance Rm <400-700 nm) is 0.62%.

[0318] Table 12 below shows the different optical characteristics Rv and Ruv of the exemplified lens 9 (AR coating Ex.9 / illuminant D65):

[0319] Table 12 In addition, Fig.18 shows the variation of the Chroma C* in the international colorimetric system L*a*b* under the standard illuminant D65 as function of the angle of incidence 0° to 75° for this ophthalmic Lens 9. The AR structure (AR Ex.9) of this Lens 9 is similar to the one of Lens 5 (AR Ex.5), but without the constraint of low Ruv requirement. C* of AR Ex-9 can be well- controlled <0.75 over AOI from 0°-75° while keeping Rv at the same level as the one of AR Ex-5. At AOI<20°, Rv values of Ex-9 are lower than <0.42% and varies slightly with AOI. Rmin occurs at 0°, Rmin / Ri5°=0.93 and Rmin / R2o°=O.85. Also, the reflectance of this stack is always lower than 4.4% over the whole visible light region 380-780 nm. Its mean reflectance Rm (400-700 nm) is 0.48%. C.3 Comparative example

[0320] Ex.9 of the document EP3884315 has been reproduced by the Applicant.

[0321] The following results have been obtained:

[0322] Table 13

[0323] It can be observed that the Chroma C* values are higher than 3 when we take into account all the angles of incidence ranging from 0° to 75°. Indeed, even if the Chroma C* values are lower than 3 at an angle of incidence of 30° or 35°, the Chroma C* values for the other angles of incidence are higher than 4.

[0324] This kind of AR coating appears therefore with a color residual reflection color for an observer.

Claims

CLAIMS1. An optical article having a front main face and a rear main face, comprising: at least one base element having a front main surface and a rear main surface, at least one multilayer antireflective coating, deposited on said front main surface and / or said rear main surface of the base substrate, which comprises at least two layers having a low refractive index which is lower than 1.55, defined as “LI layer”, and at least two layers having a high refractive index which is equal to or higher than 1.55, defined as “HI layer”, characterized in that the at least one multilayer antireflective coating is configured such that the front and / or the rear main face of the optical article has, in reflexion,- a predetermined mean light reflection factor in the visible region Rv which is lower than or equal to 1.5 %, said mean light reflection factor in the visible region Rv being as defined in the ISO 13666:1998 Standard and measured in accordance with the ISO 8980-4, under the standard illuminant D65 and an angle of incidence of 15°,- a predetermined Chroma C*, as defined in the international colorimetric CIE L*a*b* under the standard illuminant D65, which is lower than or equal to 4 for any angle of incidence between 0° to 75°.

2. The optical article according to claim 1 , wherein said predetermined C* is lower than or equal to 3, preferably lower than or equal to 2.5, preferably lower than or equal to 2 and typically lower than or equal to 1.5 for any angle of incidence between 0° to 75°.

3. The optical article according to claim 1 or 2, wherein the at least one multilayer antireflective coating is configured such that said front and / or the rear main surface of the optical article having said predetermined mean light reflection factor in the visible region Rv and said predetermined chroma C* has, in reflexion, a predetermined saturation value, S*uv, which is lower than or equal to 0.5 for any angle of incidence between 0° to 75°, said S*uv being as defined in the CIELLIV color space, under the standard illuminant D65 or the illuminant LED2700K.

4. The optical article according to any one of the preceding claims, wherein the at least one multilayer antireflective coating, which is configured such that said front and / or the rear main surface of the optical article having said predetermined mean light reflection factor in the visible region Rv and said predetermined chroma C*, has, in reflection, a predetermined saturation value, S*uv, which is lower than or equal to 0.4, preferably lower than or equal to 0.3 and typically lower than or equal to 0.3 for an angle of incidence of 15° under the standard illuminant D65 or the illuminant LED2700K.

5. The optical article according to any one of the preceding claims, wherein said predermined mean light reflection factor in the visible region Rv which is lower than or equal to 1.0%, preferably lower than or equal to 0.9%, in particular lower than or equal to 0.8%, such as lower than or equal to 0.7%, for an angle of incidence of 15°.

6. The optical article according to any one of the preceding claims, wherein the at least one multilayer antireflective coating is configured such that said front and / or the rear main surfaceof the optical article having said predetermined mean light reflection factor in the visible region Rv and said predetermined chroma C*, has, in reflection, a predetermined mean reflection factor for all wavelengths ranging from 400 nm to 700 nm, noted Rm400'700, which is lower than or equal to 1 .5 %, preferably lower than or equal to 1 .2%, preferably lower than or equal to 1 .0%, in particular lower than or equal to 0.8%, said Rm400'700being as defined in the ISO 13666:1998 Standard, and measured in accordance with the ISO 8980-4 Standard, for an angle of incidence of 15°.

7. The optical article according to any one of the preceding claims, wherein the at least one multilayer anti reflective coating is configured such that said front and / or the rear main surface of the optical article having said predetermined mean light reflection factor in the visible region Rv and said predetermined chroma C*, has a minimum mean light reflection factor in the visible region, noted Rvmin, for an angle of incidence 0min ranging from 0° to 75° and Rvmin / Rv(is°) s 1.0, preferably is within the range from 0.85 to 1 , Rv(is°) being the mean light reflection factor for an angle of incidence 0 of 15°.

8. The optical article according to any one of the preceding claims, wherein the at least one multilayer anti reflective coating is configured such that said front and / or the rear main surface of the optical article having said predetermined mean light reflection factor in the visible region Rv and said predetermined chroma C*, has a minimum mean light reflection factor in the visible region, noted Rvmin, for an angle of incidence 0min ranging from 0° to 75° and Rvmin / Rv<2o°) 1.0, preferably is within the range from 0.85 to 1 , Rv(2o") being the mean light reflection factor for an angle of incidence 0 of 20°.

9. The optical article according to any one of the preceding claims, wherein the at least one multilayer anti reflective coating is configured such that said front and / or the rear main surface of the optical article having said predetermined mean light reflection factor in the visible region Rv and said predetermined chroma C*, has, in reflection, a mean reflection factor Ruv between 280 nm and 380 nm, weighted by the function W(A) defined in the ISO 13666:1998 standard, lower than or equal to 5%, preferably lower than or equal to 4%, and typically lower than or equal to 3%, for an angle of incidence (0) of 35°10. The optical article according to any one of the preceding claims, wherein the at least one multilayered antireflective coating comprises a number of layers higher than or equal to 4, preferably higher than or equal to 5, especially higher than or equal to 6 and typically higher than or equal to 8 and a number of layers lower than or equal to 16, preferably lower than or equal to 14, more preferably lower than or equal to 12 and typically lower than or equal to 11.11 . The optical article according to any one of the preceding claims, wherein the at least multilayered antireflective coating comprises, starting from the substrate:(A) a first HI sheet, defined as “innermost HI sheet”, which preferably does not comprise any Ta2Os layer, and has in general a physical thickness lower than or equal to 50 nm, 40 nm, 30 nm, 25 nm, 20 nm, preferably lower than or equal to 15 nm;(B) a first LI sheet, defined as “innermost LI sheet” and having in general a physical thickness lower than or equal to 80 nm, preferably lower than or equal to 70 nm and typicallylower than or equal to 60 nm;(C) a second HI sheet having in general a physical thickness lower than or equal to 60 nm, more preferably lower than or equal to 50 nm, 40 nm, 30 nm, 25 nm, 20 nm or 15 nm;(D) a second LI layer, defined as “thick LI layer” which has a physical thickness higher than or equal to 50 nm, 60 nm, 70 nm, 100 nm or 110 nm, more preferably higher than or equal to 120 nm, more preferably higher than or equal to 130 nm and typically higher than or equal to 140 nm.

12. The optical article according to any one of the preceding claims, wherein the ratio of the physical thickness of LI layers: physical thickness of HI layers is higher than or equal to 0.9, preferably higher than or equal to 1.0 and typically higher than or equal to 1.5, such as higher than or equal to 2.0.

13. The optical article according to any one of the preceding claims, wherein the optical article is a tinted optical article or a sunglass optical article including a dye and / or pigments, said a tinted optical article or a sunglass optical article comprises one of the said at least one multilayered antireflective coating coated on the front main face and / or on the rear main surface of the base element.

14. The optical article according to any one of the claims 1 to 12, wherein the optical article is:- a clear optical article having, in reflection, on its front main face and / or and on its rear main face, a transmission factor in the visible range Tv, which is higher than 90%, more preferably higher than 95%, even more preferably higher than 96% and most preferably higher than 97%, or- a blue cut optical article comprising a selective filter blocking, at least partially, blue light in a wavelength range chosen within the 400- 460 nm range; or- a photochromic optical article, or- an electrochromic optical article, which comprises two of the said at least one multilayered antireflective coatings coated respectively on the front main face and on the rear main face.

15. Eyewear device comprising at least an optical article having a front main face and a rear main face, comprising: at least one base element having a front main surface and a rear main surface, at least one multilayer antireflective coating, deposited on said front main surface and / or said rear main surface of the base substrate, which comprises at least two layers having a low refractive index which is lower than 1.55, defined as “LI layer”, and at least two layers having a high refractive index which is equal to or higher than 1.55, defined as “HI layer”, characterized in that the at least one multilayer antireflective coating is configured such that the front and / or the rear main surface of the optical article has, in reflexion,- a predetermined mean light reflection factor in the visible region Rv which is lower than or equal to 1.5 %, said mean light reflection factor in the visible region Rv being as defined in theISO 13666:1998 Standard and measured in accordance with the ISO 8980-4, under the standard illuminant D65 and an angle of incidence of 15°,- a predetermined Chroma C*, as defined in the international colorimetric CIE L*a*b* under the standard illuminant D65, which is lower than or equal to 4 for any angle of incidence between 0° to 75°.

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