Optical article having a non-visible multilayer antireflective coating

Abstract

The invention relates 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 element, 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", said at least one multilayer antireflective coating is configured to provide to said optical article has improved colorimetric and optical characteristics.

Description

[0001] Optical article having a non-visible multilayer antireflective coating

[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.

[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 anti refl ection 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 gets 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 try 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 turns out to be 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 either 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 strong residual color in reflection for an observer (such as a green, blue or purple residual reflection color) which also modifies the skin and eye coloration, or a higher reflection in the visible region (i.e.: such a mean light reflection factor in the visible region Rv which is higher than 0.5%), but also a discernible reflection for an observer which can appear white or colored (e.g. green, blue, purple). These residual clear or colored reflections, 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 maintain stable properties despite the variations induced by its manufacturing process. These variations depend, for instance, on the type of substrate which is used, the setting of the manufacturing machine (e.g. temperature schedule, appropriate time, 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] Therefore, an object of the current invention is thus to propose a new optical article which avoids, at least in part, the aforementioned drawbacks.

[0017] In particular, it would be desirable to improve the aesthetic appearance of such an optical article by obtaining, for instance, a homogenous 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 anti refl ection 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.

[0018] 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 aesthetic appearance whatever the angles of incidence and preferably robustness properties.

[0019] SUMMARY OF THE INVENTION

[0020] The Applicant sought to develop a new optical article having a very low reflectivity on its front face and / or rear main face, while having excellent colorimetric properties and this whatever the angles of incidence.

[0021] 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 element, 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”, said optical article has, on its front main face, a front mean light reflection factor in the visible region, defined as Rv(front) and a front saturation value, defined as S*uv(front), on its rear main face, a rear mean light reflection factor in the visible region, defined as Rv(rear) and a rear saturation value, defined as S*uv(rear), an average of mean light reflection factors, defined as average Rv, and corresponding to (Rv(front) + Rv(rear)) / 2 and an average of saturation values, defined as average S*uv, corresponding to (S*uv(front) + S*uv(rear)) / 2, characterized in that the at least one multilayer antireflective coating is configured to provide to the optical article, in reflection, under the standard illuminant D65 and for an angle of incidence of 15° the following predetermined optical conditions: at least one of Rv(front), Rv(rear) and average Rv is lower than or equal to 0.6 % for, respectively, S*uv(front), S*uv(rear) and average S*uv lower than or equal to 0.8, or

[0022] - at least one of Rv(front), Rv(rear) and average Rv is lower than or equal to 0.3% for, respectively, S*uv(front), S*uv(rear) and average S*uv lower than or equal to 1.2, said Rv(front) or Rv(frear) being as defined in the ISO 13666:1998 Standard and measured in accordance with the ISO 8980-4: 2006, said S*uv(front) or S*uv(rear) being as defined in the CIELLIV color space.

[0023] The Applicant has found that such an antireflective coating having a low Rv, a low S*uv and preferably specific colorimetric coefficients a* and b* 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.

[0024] BRIEF DESCRIPTION OF THE DRAWING

[0025] 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.

[0026] FIG. 1 is a graph showing the coefficients a*, on abscissa, and b*, on ordinate, taking the standard illuminant D65, at angle of 15°, 30° to 45° for examples A to E according to the invention;

[0027] FIG. 2 shows the saturation value S*uv as a function of Rv, taking the standard illuminant D65, at an angle of 15° for lenses 2, 3, 7, 8, 9 and 10 according to the invention.

[0028] DETAILED DESCRIPTION OF THE INVENTION

[0029] A) Definitions

[0030] 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.

[0031] 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."

[0032] 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.

[0033] 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.

[0034] 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).

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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. 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.

[0042] Also, unless stated otherwise, all thicknesses disclosed in the present application relate to physical thicknesses.

[0043] 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. 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.

[0044] Unless otherwise specified, the refractive indexes referred to in the present application are expressed at 25 °C at a wavelength of 550 nm.

[0045] 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.

[0046] 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.

[0047] The optical characteristics comprise at least the mean light reflection factor in the visible region Rv, also named the "luminous reflectance".

[0048] Herein, the "luminous reflectance" noted Rv, should be understood as defined in the ISO 13666:1998 standard, and measured in accordance with the ISO 8980-4:2006. It is defined in the wavelength range of from 380 to 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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).

[0055] 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).

[0056] The mean reflection factor Ruv is measured in the present application at an angle of incidence of 35°.

[0057] 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* = 7(a‘2+ b*2) defines the chromaticness. The angle of hue: h = tan-1(h* / cT) (expressed in degrees) relates to the hue.

[0058] 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°.

[0059] 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 taking into account the standard llluminant D65. However, some examples have also been done with the illuminant LED2700K. In this case, this illuminant LED270K is specifically specified.

[0060] According to the invention, the colorimetric measurements (in reflection) of the at least one face coated with the antireflective multilayered coating of the invention : reflection factors Rv, hue angle h, and chroma C* in the international colorimetric CIE (L*, a*, b*) space were carried out with a Zeiss spectrophotometer, taking into account either the standard illuminant D65 or the illuminant LED2700K, and the standard observer 10° (for h and C*). They are provided for angles within the range from 0° to 45°.

[0061] 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° and is typically 15° for the present invention.

[0062] B) Optical article according to the invention

[0063] 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.

[0064] The optical article is such as defined in the set of claims and has 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 element, 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”, said optical article has, on its front main face, a front mean light reflection factor in the visible region, defined as Rv(front) and a front saturation value, defined as S*uv(front), on its rear main face, a rear mean light reflection factor in the visible region, defined as Rv(rear) and a rear saturation value, defined as S*uv(rear), an average of mean light reflection factors, defined as average Rv, and corresponding to (Rv(front) + Rv(rear)) / 2 and an average of saturation values, defined as average S*uv, corresponding to (S*uv(front) + S*uv(rear)) / 2, characterized in that the at least one multilayer antireflective coating is configured to provide to the optical article, in reflection, under the standard illuminant D65 and for an angle of incidence of 15° the following predetermined optical conditions: at least one of Rv(front), Rv(rear) and average Rv is lower than or equal to 0.6 % for, respectively, S*uv(front), S*uv(rear) and average S*uv lower than or equal to 0.8, or

[0065] - at least one of Rv(front), Rv(rear) and average Rv is lower than or equal to 0.3% for, respectively, S*uv(front), S*uv(rear) and average S*uv lower than or equal to 1.2, said Rv(front) or Rv(frear) being as defined in the ISO 13666:1988 standard and measured in accordance with the ISO 8980-4: 2006, said S*uv(front) or S*uv(rear) being as defined in the CIELLIV color space The structure of the base element (A) will be described hereafter.

[0066] B.1 The base element / substrate

[0067] 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.

[0068] 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 (TAG) 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 (TAG), cellulose acetate butyrate (CAB), polycarbonate (PC), poly(ethylene terephthalate) (PET), poly(methylmethacrylate) (PMMA), urethane polymer (TPU), cyclo olefin copolymer (COG), polyester copoblock amide (like Pebax) and Polyimides.

[0069] 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.

[0070] 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. Thermoplastic may be selected from, for instance: polyamides; polyimide; polysulfones; polycarbonates and copolymers thereof; poly(ethylene terephthalate) and polymethylmethacrylate (PMMA).

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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). B.2 The multilayered anti reflective coating

[0078] As previously mentioned, the optical article according to the invention comprises at least one specific multilayer antireflective coating (named hereafter AR coating), deposited on the main surface and / or the rear main surface of the base element, 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”.

[0079] According to the invention, the AR coating enables to provide to the optical article specific optical and colorimetric characteristics. Indeed, it is configured to provide to the optical article, in reflection, under the standard illuminant D65 and for an angle of incidence of 15° the following predetermined optical and colorimetric conditions: at least one of Rv(front), Rv(rear) and average Rv, in particular at least two from Rv(front), Rv(rear) and average Rv and especially Rv(front), Rv(rear) and average Rv is / are lower than or equal to 0.6 % for, respectively, S*uv(front), S*uv(rear) and average S*uv lower than or equal to 0.8, or at least one of Rv(front), Rv(rear) and average Rv, in particular at least two from Rv(front), Rv(rear) and average Rv and especially Rv(front), Rv(rear) and average Rv is / are lower than or equal to 0.3% for, respectively, S*uv(front), S*uv(rear) and average S*uv lower than or equal to 1.2.

[0080] According to another aspect, the AR coating according to the invention is also configured / able to provide to the front main face of the optical article, in reflection, a very low reflection when another illuminant is used instead of the standard illuminant D65, especially the illuminant LED 2700K. This illuminant LED 2700K is a warm source and is representative of domestic lighting for indoor situations, whereas the illuminant D65 light source is a colorimetry standard based on daylight.

[0081] According to this aspect, by using an illumination LED 2700K instead of the standard illuminant D65 and an angle of incidence of 15°, the multilayer antireflective coating is configured so as to provide to the optical article the following predetermined optical conditions: at least one of Rv(front), Rv(rear) and average Rv, in particular at least two from Rv(front), Rv(rear) and average Rv and especially Rv(front), Rv(rear) and average Rv is / are lower than or equal to 0.6 % for, respectively, S*uv(front), S*uv(rear) and average S*uv lower than or equal to 0.8, or at least one of Rv(front), Rv(rear) and average Rv, in particular at least two from Rv(front), Rv(rear) and average Rv and especially Rv(front), Rv(rear) and average Rv is / are lower than or equal to 0.3% for, respectively, S*uv(front), S*uv(rear) and average S*uv lower than or equal to 1.2, preferably lower than or equal to 1 .0; or at least one of Rv(front), Rv(rear) and average Rv, in particular at least two from Rv(front), Rv(rear) and average Rv and especially Rv(front), Rv(rear) and average Rv is / are lower than or equal to 0.4% for, respectively, S*uv(front), S*uv(rear) and average S*uv lower than or equal to 1 , preferably lower than or equal to 0.65.

[0082] In general, the Applicant has found that Rv and S*uv (front, rear or average) are lower under the illuminant LED2700K as compared to the standard illuminant D65.

[0083] As used hereafter, except indicated otherwise, the optical characteristics, such as Rv(front), Rv(rear) and average Rv and the colorimetric characteristics, such as S*uv(front), S*uv(rear) and average S*uv are given for both standard illuminant D65 and illuminant LED2700K (the same characteristics are obtained whatever the Illuminant) and for an angle of incidence of 15°.

[0084] Especially, at least one of Rv(front), Rv(rear) and average Rv, in particular at least two from Rv(front), Rv(rear) and average Rv and especially Rv(front), Rv(rear) and average Rv is / are lower than or equal to 0.55%, preferably lower than or equal to 0.45 % for, respectively, S*uv(front), S*uv(rear) and average S*uv lower than or equal to lower than or equal to 0.8, preferably lower than or equal to 0.75.

[0085] As used herein, “at least one of Rv(front), Rv(rear) and average Rv which is lower than or equal to 0.6 %” includes the following values (in %) and / or any intervals comprised between these values: 0.6; 0.55; 0.50; 0.45; 0.40; 0.35; 0.30; 0.25; 0.20; 0.15, etc. such as within the range from: 0.15 to 0.6, 0.15 to 0.55; 0.15 to 0.50; 0.15 to 0.45; 0.15 to 0.35; 0.15 to 0.30; 0.15 to 0.25; 0.20 to 0.55; “at least one of Rv(front), Rv(rear) and average Rv which is lower than or equal to 0.40 %” includes the following values (in %) and / or any intervals comprised between these values: 0.40; 0.35; 0.30; 0.25; 0.20; 0.15, etc. such as within the range from: 0.15 to 0.4; 0.15 to 0.35; 0.15 to 0.30; 0.15 to 0.25, 0.15 to 0.20; and “at least one of Rv(front), Rv(rear) and average Rv which is lower than or equal to 0.3 %” includes the following values (in %) and / or any intervals comprised between these values: 0.30; 0.25; 0.20; 0.15, etc. such as within the range from: 0.15 to 0.3; 0.15 to 0.25; 0.15 to 0.20; 0.20 to 0.25.

[0086] Also, as used herein, “a saturation value S*uv(front) or S*uv(rear) or average S*uv lower than or equal to 0.8” includes the following values and / or any intervals comprised between these values: 0.8; 0.75; 0.70; 0.65; 0.60; 0.55; 0.50; 0.45; 0.40; 0.35; 0.30; 0.25; 0.20; 0.15, etc. such as within the range from: 0.15 to 0.8; 0.15 to 0.75; 0.15 to 0.65; 0.15 to 0.60; 0.15 to 0.55; 0.15 to 0.50; 0.15 to 0.45; 0.20 to 0.75; 0.20 to 0.65, also, “a saturation value S*uv(front) or S*uv(rear) or average S*uv lower than or equal to 0.65” includes the following values and / or any intervals comprised between these values: 0.65; 0.60; 0.55; 0.50; 0.45; 0.40; 0.35; 0.30; 0.25; 0.20; 0.15, etc. such as within the range from: 0.15 to 0.65; 0.15 to 0.60; 0.15 to 0.55, 0.15 to 0.50; 0.15 to 0.45; 0.20 to 0.60; 0.20 to 0.55; 0.20 to 0.50 and “a saturation value S*uv(front) or S*uv(rear) or average S*uv lower than or equal to 1.2” includes the following values and / or any intervals comprised between these values: : 1.20; 1.15; 1.10; 1.0; 0.9; 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; 0.20; 0.15, etc, such as within the range from 0.15 to 1.20; 0.15 to 1.15; 0.15 to 1.10; 0.15 to 1.0; 0.15 to 0.9; 0.15 to 0.85; 0.15 to 0.80; 0.15 to 0.75; 0.20 to 1.15; 0.20 to 1.10; 0.20 to 1.0

[0087] Generally, at least one of Rv(front), Rv(rear) and average Rv, in particular at least two from Rv(front), Rv(rear) and average Rv and typically Rv(front), Rv(rear) and average Rv is / are higher than 0.10, in particular higher than or equal to 0.15, especially higher than or equal to 0.20, and typically higher than or equal to 0.25.

[0088] Also, at least one of S*uv(front), S*uv(rear) and average S*uv, in particular at least two from S*uv(front), S*uv(rear) and average S*uv and especially S*uv(front), S*uv(rear) and average S*uv is / are is higher than 0.10, in particular higher than or equal to 0.15, especially higher than or equal to 0.20, and typically higher than or equal to 0.25.

[0089] For instance, at least one of Rv(front), Rv(rear) and average Rv, in particular at least two from Rv(front), Rv(rear) and average Rv and typically Rv(front), Rv(rear) and average Rv is / are within the range from 0.1 % to 0.6% for, respectively, S*uv(front), S*uv(rear) and average S*uv within the range from 0.1 to 0.8, or at least one of Rv(front), Rv(rear) and average Rv, in particular at least two from Rv(front), Rv(rear) and average Rv and typically Rv(front), Rv(rear) and average Rv is within the range from 0.1 % to 0.3% for, respectively, S*uv(front), S*uv(rear) and average S*uv within the range from 0.1 to 1.2.

[0090] In general, the at least one multilayer antireflective coating is configured so as to provide to the optical article, in reflection (whatever the llluminant of for an angle of incidence of 15°), Rv(front) and Rv(rear) that fulfill said predetermined optical and colorimetric conditions:

[0091] - Rv(front) and Rv(rear) are each lower than or equal to 0.6 % for S*uv(front) and S*uv(rear) being each lower than or equal to 0.8, or

[0092] - Rv(front) and Rv(rear) are each than or equal to 0.3% for S*uv(front) and S*uv(rear) being each lower than or equal to 1 .2.

[0093] Also, the at least one multilayer antireflective coating may be configured so as to provide to the optical article, in reflection (whatever the llluminant of for an angle of incidence of 15°), Rv(front) and Rv(rear) that fulfill said predetermined optical and colorimetric conditions:

[0094] - average Rv which is lower than or equal to 0.6 % for average S*uv lower than or equal to 0.8, or

[0095] - average Rv which is lower than or equal to 0.3% for average S*uv lower than or equal to 1.2.

[0096] In addition, the at least one multilayer antireflective coating may be configured so as to provide to the optical article, in reflection (whatever the llluminant of for an angle of incidence of 15°), Rv(front) and Rv(rear) that fulfill said predetermined optical and colorimetric conditions:

[0097] - Rv(front), Rv(rear) and average Rv which are each lower than or equal to 0.6 % for, respectively, S*uv(front), S*uv(rear) and average S*uv lower than or equal to 0.8, or

[0098] - Rv(front), Rv(rear) and average Rv which are each lower than or equal to 0.3% for, respectively, S*uv(front), S*uv(rear) and average S*uv lower than or equal to 1.2.

[0099] According to an aspect of the invention, the at least one multilayer antireflective coating is coated on the front main surface of the base element and is configured to provide to the optical article (whatever the llluminant of for an angle of incidence of 15°), Rv(front) lower than or equal to 0.6 % for S*uv(front) lower than or equal to 0.8 or Rv(front) lower than or equal to 0.3 % for S*uv(front) lower than or equal to 1.2.

[0100] According to another aspect of the invention (that may be combined or not with the previous one), the at least one multilayer antireflective coating is coated on the rear main surface of the base element and is configured to provide to the optical article (whatever the llluminant of for an angle of incidence of 15°), Rv(rear) lower than or equal to 0.6 % for S*uv(rear) lower than or equal to 0.8 or Rv(rear) lower than or equal to 0.3 % for S*uv(rear) lower than or equal to 1.2.

[0101] According to another aspect of the invention (that may be combined or not to the previous ones), the base element is coated on its front main surface and on its rear main surface with the at least multilayer antireflective coating as defined above. According to a characteristic of the invention, the at least multilayer antireflective coating coated on the front main surface (defined as AR1) is similar / identical to the at least multilayer antireflective coating coated on rear main surface (defined as AR2). According to another characteristic of the invention, the at least multilayer antireflective coating coated on the front main surface (AR1) is different from the at least multilayer antireflective coating coated on rear main surface (defined as AR2). In particular, these two multilayer antireflective coatings AR1 and AR2 are configured to provide to the optical article, average Rv lower than or equal to 0.6 % for average S*uv lower than or equal to 0.8 or average Rv lower than or equal to 0.3 % for average S*uv lower than or equal to 1.2. According to this aspect of the invention, AR1 and / or AR2 may also be configured to provide to the optical article, respectively, Rv(front) lower than or equal to 0.6 % for S*uv(front) lower than or equal to 0.8 or Rv(front) lower than or equal to 0.3 % for S*uv(front) lower than or equal to 1 .2.

[0102] Indeed, according to an embodiment, the optical article may comprise two of said at least one multilayered antireflective coatings, coated respectively on its the front main face and on its the rear main face, each multilayered antireflective coating being configured so as to fulfill said predetermined optical and colorimetric conditions, and especially average Rv lower than or equal to 0.6 % for average S*uv lower than or equal to 0.8, or average Rv lower than or equal to 0.3% for average S*uv lower than or equal to 1 .2.

[0103] According to another aspect, the AR coating according to the invention is also configured / able to provide to the rear main face of the optical article, in reflection, a very reflection in the UV range, especially at an angle of incidence ranging from 0 to 45°, such as equal to 35°.

[0104] Indeed, the AR may be configured so that the rear main surface of the optical article has, in reflection, a mean reflection factor Ruv between 280 nm and 380 nm 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°.

[0105] According to the invention, “Ruv which is lower than or equal to 5.0 %” includes the following values (in %) and / or any intervals comprised between these values: 5.0; 4.9; 4.8; 4.7; 4.6; 1.5; 4.4; 4.3; 4.2; 4.1 ; 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; 1.0; etc., such as within the range from:1.0 to 5.0, 1.0 to 4.8; 1.0 to 4.5; 1.0 to 4.0; 1.0 to 3.5; 1.5 to 5.0; 1.5 to 4.7.

[0106] Hence, the AR coating may have also very good antireflective characteristics in the UV bands. 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).

[0107] Moreover, the AR coating according to the invention is also characterized by improved colorimetric characteristics in reflection and especially a very low a*, b*and Chroma C* values and this, for all the angles of incidence ranging from 15° to 45°.

[0108] Hereafter, the colorimetric characteristics (such as a*, b*, C*) are given under the standard illuminant D65 and for an angle of incidence ranges from 15° to 45° and the other characteristics (such as Rv and S*uv) are given under the standard illuminant D65 and for an angle of incidence of 15°

[0109] Especially, the optical article according to the invention has, on its front main face, front colorimetric coefficients a*, b* and C*, defined respectively as a*(front), b*(front) and C*(front), on its rear main face, rear colorimetric coefficients a*, b* and C*, defined respectively as a*(rear), b*(rear) and C*(rear).

[0110] According to an aspect of the invention, the at least one multilayer antireflective coating is configured so as to provide to the optical article, in reflection:

[0111] Rv(front) is lower than or equal to 0.6 % for S*uv(front) lower than or equal to 0.8 or Rv(front) is lower than or equal to 0.3 % for S*uv(front) lower than or equal to 1.2 for an angle of incidence of 15° and a*(front) < 3 for b*(front) < 0 or -3 < a*(front) < 3 for 0 < b*(front) < 3 or C*(front) < 2 for b*(front) > 0, for all angles of incidence comprised between 0° and 45°, especially from 15° to 45°.

[0112] In general, in that aspect of the invention, the at least one multilayer antireflective coating is coated on the front main surface of the base element.

[0113] According to another aspect (that may be combined or not to the previous one), the at least one multilayer antireflective coating is configured so as to provide to the optical article, in reflection:

[0114] Rv(rear) is lower than or equal to 0.6 % for S*uv(rear) lower than or equal to 0.8 or Rv(rear) is lower than or equal to 0.3 % for S*uv(rear) lower than or equal to 1.2 for an angle of incidence of 15° and a*(rear) < 3 for b*(rear) < 0 or -3 < a*(rear) < 3 for 0 < b*(rear) < 3 or c*(rear) < 2 for b*(rear) > 0, for all angles of incidence comprised between 0° and 45°, especially from 15° to 45°.

[0115] In general, in that aspect of the invention, the at least one multilayer antireflective coating is coated on the rear main surface of the base element.

[0116] According to another aspect (that may be combined or not to the previous ones), the at least one multilayer antireflective coating is configured so as to provide to the optical article, in reflection: average Rv is lower than or equal to 0.6 % for average S*uv lower than or equal to 0.8 or average Rv is lower than or equal to 0.3 % for average S*uv lower than or equal to 1 .2 for an angle of incidence of 15° and a*(front) < 3 for b*(front) < 0 or -3 < a*(front) < 3 for 0 < b*(front) < 3 or C*(front) < 2 for b*(front) > 0, for all angles of incidence comprised between 0° and 45°, especially from 15° to 45°.

[0117] In general, in that aspect of the invention, the at least one multilayer antireflective coating is coated on the front main surface and on the rear main surface of the base element.

[0118] In particular, the at least one multilayer antireflective coating is configured so that:

[0119] Rv(front) lower than or equal to 0.6 % for S*uv(front) lower than or equal to 0.8 or Rv(front) lower than or equal to 0.3 % for S*uv(front) lower than or equal to 1.2 for an angle of incidence of 15°, and a*(front) < 3 for b*(front) < 0 or -3 < a*(front) < 3 for 0 < b*(front) < 3 or C*(front) < 2 for b*(front) > 0, for all angles of incidence comprised between 0° and 45°, especially from 15° to 45°; and

[0120] Rv(rear) lower than or equal to 0.6 % for S*uv(rear) lower than or equal to 0.8 or Rv(rear) lower than or equal to 0.3 % for S*uv(rear) lower than or equal to 1 .2 for an angle of incidence of 15°, and a*(rear) < 3 for b*(rear) < 0 or -3 < a*(rear) < 3 for 0 < b*(rear) < 3 or C*(rear) < 2 for b*(rear) > 0, for all angles of incidence comprised between 0° and 45°, especially from 15° to 45°.

[0121] According to the invention, ““a*(front) or a*(rear) < 3” includes the following values and / or any intervals comprised below these values: 3.0; 2.5; 2.0; 1.5; 1 .0; 0.5; 0.0; -0.5; -1.0; -1.5; -2.0; -2.5; -3.0; -3.5; -4.0; -4.5; -5.0; -5.5; -6.0; -6.5; -7.0; etc, such as within the range from: -7 to 3.0; -7 to 2.5; -7 to 2.0; -6.0 to 2.5; -6.0 to 2.0.

[0122] In particular, the colorimetric coefficients a*(front) or a*(rear) falls within the range - 3 < a* < 2, especially within the range -2 < a* < 2 for all angles of incidence comprised between 0° and 45°.

[0123] According to another characteristic of the invention, the AR coating is configured so that the front main face of the optical article, has in reflection, the colorimetric coefficient b* which falls within the ranges b*(front) or b*(rear) < 3 for all angles of incidence comprised between 0° and 45°, taking the standard illuminant D65.

[0124] In general, “b*(front) or b*(rear) < 3” includes the following values and / or any intervals comprised below these values: 3.0; 2.5; 2.0; 1.5; 1.0; 0.5; 0.0; -0.5; -1.0; -1.5; -2.0; -2.5; -3.0; - 3.5; -4.0; -4.5; -5.0; -5.5; -6.0; -6.5; -7.0; etc., such as within the range from : -7 to 3.0; -7 to 2.5; -7 to 2.0; -6.0 to 2.5; -6.0 to 2.0.

[0125] Generally, the colorimetric coefficients b*(front) or b*(rear) falls within the range b*(front), b*(rear) < 2.5, preferably b*(front) or b*(rear) < 2.0 and typically b* (front) or b*(rear) < 1.5 for all angles of incidence comprised between 0° and 45°.

[0126] Typically, the colorimetric coefficients b*(front), b*(rear) falls within the range b*(front), b*(rear) < 0 for all angles of incidence comprised between 0° and 45° taking the standard illuminant D65.

[0127] According to another characteristic of the invention, the AR coating is configured so that the front main surface of the optical article has, in reflection and for all angles of incidence comprised between 0° and 45°, a Chroma, C*(front) and / or C*(rear) lower than or equal to 6, preferably lower than or equal to 5, especially lower than or equal to 4 and advantageously, the Chroma is lower than or equal to 2 when the colorimetric coefficient b*(front) and / or b*(rear) > 0, said Chroma is as defined in the international colorimetric CIE L*a*b* taking the standard illuminant D65.

[0128] Hence, whatever the angle of incidence ranging from 0° to 45°, C* is low. Here, “C*(front) and / or C*(rear) < 6” includes the following values and / or any intervals comprised between these values: 6.0; 5.5; 5.0; 4.5; 4.0; 3.5; 3.0; 2.5; 2.0; 1.5; 1.0; etc. such as within the range from 1.0 to 6.0.

[0129] Therefore, even if the hue may vary (generally slightly), as function as the angle of incidence, since the Chroma C*(front) and / or C*(rear) is low (typically lower than or equal to 3) and since the saturation S*uv described above is extremely low, the color change of the residual reflection of the AR coating is not perceptible for an observer.

[0130] The structure of the AR coating will now be described hereafter.

[0131] According to the invention, the AR coating 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. 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.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] In general, the HI layers and LI layers alternate with each other in the stack of the AR coating according to the invention.

[0136] 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.

[0137] 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.

[0138] According to a characteristic of the invention, one of the LI layers of said multilayer antireflective coating is a LI layer, defined as “thick LI layer” (named hereafter (D)), which has a physical thickness higher than or equal to 100 nm, especially higher than or equal to 120 nm, preferably higher than or equal to 130 nm and typically higher than or equal to 140 nm, and is, starting from the base element / substrate, the second LI layer among all the LI layers of the multilayer antireflective coating.

[0139] Generally, the at least one multilayered antireflective coating comprises, in the direction moving away from the substrate:

[0140] - a HI layer or HI sheet, which is in innermost position among all the HI layers of multilayered antireflective coating, named “innermost HI layer or innermost HI sheet”, which has a physical thickness of 50 nm or less, preferably of 40 nm or less, especially of 30 nm or less, preferably of 25 nm or less, in particular of 20 nm or less and which is in general the innermost layer among all the layers composing the multilayer antireflective coating;

[0141] - a LI layer or LI sheet, which is in innermost position among all the LI layers of the multilayered antireflective coating, named “innermost LI layer or innermost LI sheet”, which has a physical thickness of at least 10 nm, preferably of at least 20 nm, in particular of at least 30 nm, and typically of at least 40 nm and preferably lower than or equal to 100 nm, preferably lower than or equal to 90 nm, and typically lower than or equal to 80 nm;

[0142] - generally, the innermost HI layer is coated, preferably directly coated, with the innermost LI layer, or inversely.

[0143] According to an embodiment of the invention, the AR coating comprises generally successively (i.e.: in direct contact), starting from the substrate / base element:

[0144] (A) a first HI sheet that may correspond to the above-mentioned “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;

[0145] (B) a first LI sheet that may correspond to the above-mentioned “innermost LI sheet” and having in general a physical thickness lower than or equal to 90 nm, preferably lower than or equal to 80 nm and typically lower than or equal to 70 nm;

[0146] (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;

[0147] (D) a second LI layer, which corresponds to the above-mentioned “thick LI layer” which has a physical thickness higher than or equal to 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.

[0148] 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.

[0149] 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.

[0150] Sheet (A) preferably has a thickness higher than or equal to 4 nm, more preferably higher than or equal to 5 nm.

[0151] 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.

[0152] 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.

[0153] 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.

[0154] 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.

[0155] 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.

[0156] 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.

[0157] 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.

[0158] 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.

[0159] 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.

[0160] 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 110 nm, more preferably from 45 to 105nm or from 50 to 100 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 comprises, in the direction moving away from the substrate, 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 110, 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] According to an embodiment of the invention, the AR coating comprises generally successively (i.e: in direct contact), starting from the substrate / base element:

[0173] (A’) an optional first HI layer that may correspond to the above-mentioned “innermost HI layer”, which preferably comprises Ta2Os material, 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, such as lower than or equal to 15 nm;

[0174] (B’) a first LI layer that may correspond to the above-mentioned “innermost LI layer” and having in general a physical thickness lower than or equal to 90 nm, preferably lower than or equal to 80 nm and typically lower than or equal to 70 nm, such as lower than or equal to 60 nm.

[0175] (C’) a second HI layer, which preferably comprises Ta2Os material, 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;

[0176] (D) a second LI layer, which corresponds to the above-mentioned “thick LI layer” which has a physical thickness higher than or equal to 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.

[0177] According to this embodiment, the thick LI layer has a physical thickness higher than or equal to 150 nm, preferably higher than or equal to 160 nm, especially higher than or equal to 170 nm, and typically higher than or equal to 170 nm.

[0178] Layers (A’) and (C’) preferably comprises a Ta2Os-based layer, more preferably is a Ta2Os- based layer. In one embodiment, sheet (C) comprises a Ta2Os layer, more preferably is a Ta2Os layer.

[0179] Layer (B’) is similar to layer (B) defined above.

[0180] These layers (A’), (B’), (C’) and (D) may also be deposited according to the method described in the document EP 3 884 315, paragraphs 0167-0171 (incorporated here by reference).

[0181] In addition, 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.

[0182] 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.

[0183] In addition, according to an aspect of the invention, the ratio RTI as defined:

[0184] R TI= (sum of the physical thickness of the low refractive index layers of the anti reflective coating and located above the thick LI layer in the direction moving away from the substrate) / (sum of the physical thickness of the high refractive index layers of the antireflective coating and located above the thick LI layer in the direction moving away from the substrate), is higher than or equal to 0.8, preferably higher than or equal to 0.7 and typically higher than or equal to 0.9, such as higher than or equal to 1 .0.

[0185] According to another aspect of the invention, the ratio RTI 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, especially lower than or equal to 4.5 and typically lower than or equal to 4.

[0186] This specific ration enables also to improve the mechanical properties of the obtained AR coatings.

[0187] 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.

[0188] Preferably, the one or more HI layers are made of zirconia (ZrO2) and / or tantalum pentoxide (Ta2Os).

[0189] 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.

[0190] 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.

[0191] 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.

[0192] 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).

[0193] 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.

[0194] 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.

[0195] 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.

[0196] 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.

[0197] 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.

[0198] According to a characteristic of the invention, the different layers of the AR coatings are adjacent or successively deposited. According to another characteristic of the invention, the different layers of the AR coatings are not adjacent. Typically, the different layers of the AR coatings are adjacent or successively deposited.

[0199] According to one embodiment of the invention, the AR coating comprises, in order starting from the substrate / base element, which is optionally coated with one or more functional coatings,

[0200] (1) the first HI sheet (A), defined as “innermost HI sheet” or innermost HI layer, 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;

[0201] (2) the first LI sheet (B), defined as “innermost LI sheet” and having in general a physical thickness lower than or equal to 90 nm, preferably lower than or equal to 80 nm and typically lower than or equal to 70 nm;

[0202] (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;

[0203] (4) the second LI layer (D), defined as “thick LI layer” which has a physical thickness higher than or equal to 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 60 nm, in particular ranging from 10 nm to 50 nm, preferably ranging from 10 nm to 40 nm, and typically ranging from 15 nm to 30 nm;

[0204] (6) a LI layer having a physical thickness lower than or equal to 60 nm, in particular ranging from 5 nm to 55 nm, preferably ranging from 10 nm to 45 nm, and typically ranging from 15 nm to 35 nm,

[0205] (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,

[0206] (8) an optional LI layer having a physical thickness lower than or equal to 40 nm, in particular ranging from 2 nm to 35 nm, preferably ranging from 3 nm to 25 nm, and typically ranging from 5 nm to 15 nm,

[0207] (9) optional HI layer having a physical thickness lower than or equal to 60 nm, in particular ranging from 10 nm to 50 nm, preferably ranging from 15 nm to 45 nm, and typically ranging from 25 nm to 40 nm;

[0208] (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;

[0209] (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.

[0210] According to another embodiment of the invention, the AR coating comprises, in order starting from the substrate / base element, which is optionally coated with one or more functional coatings,

[0211] (1) the first HI sheet (A), defined as “innermost HI sheet” or innermost HI layer, 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;

[0212] (2) the first LI sheet (B), defined as “innermost LI sheet” and having in general a physical thickness lower than or equal to 90 nm, preferably lower than or equal to 80 nm and typically lower than or equal to 70 nm;

[0213] (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;

[0214] (4) the second LI layer (D), defined as “thick LI layer” which has a physical thickness higher than or equal to 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;

[0215] (5) a HI layer, such as a TiC>2 layer, having a physical thickness lower than or equal to 40 nm, in particular ranging from 2 nm to 35 nm, preferably ranging from 3 nm to 25 nm, and typically ranging from 5 nm to 15 nm, (6) a LI layer having a physical thickness lower than or equal to 40 nm, in particular ranging from 2 nm to 35 nm, preferably ranging from 3 nm to 25 nm, and typically ranging from 5 nm to 15 nm,

[0216] (7) a HI layer, such as a TiC>2 layer, having a physical thickness lower than or equal to 40 nm, in particular ranging from 2 nm to 35 nm, preferably ranging from 3 nm to 25 nm, and typically ranging from 5 nm to 15 nm,

[0217] (8) a LI layer having a physical thickness lower than or equal to 40 nm, in particular ranging from 2 nm to 35 nm, preferably ranging from 3 nm to 25 nm, and typically ranging from 5 nm to 15 nm,

[0218] (9) a HI layer, such as a TiC>2 layer, having a physical thickness lower than or equal to 120 nm, in particular ranging from 65 nm to 110 nm, preferably ranging from 70 nm to 100 nm, and typically ranging from 75 nm to 90 nm;

[0219] (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;

[0220] (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.

[0221] 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,

[0222] (1) an optional first HI sheet (A’), defined as “innermost HI sheet” or innermost HI layer, which preferably comprises Ta2Os material, 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, such as lower than or equal to 15 nm;

[0223] (2) the first LI sheet (B’), defined as “innermost LI sheet” and having in general a physical thickness lower than or equal to 90 nm, preferably lower than or equal to 80 nm and typically lower than or equal to 70 nm;

[0224] (3) the second HI sheet (C’) which preferably comprises Ta2Os material, 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;

[0225] (4) the second LI layer (D), defined as “thick LI layer” which corresponds to the above- mentioned “thick LI layer” which has a physical thickness higher than or equal to 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;

[0226] (5) a HI layer having a physical thickness lower than or equal to 55 nm, in particular ranging from 5 nm to 50 nm, preferably ranging from 8 nm to 40 nm, and typically ranging from 10 nm to 30 nm;

[0227] (6) a LI layer having a physical thickness lower than or equal to 55 nm, in particular ranging from 5 nm to 50 nm, preferably ranging from 8 nm to 40 nm, and typically ranging from 10 nm to 30 nm; (7) an optional HI layer having a physical thickness lower than or equal to 100 nm, in particular ranging from 10 nm to 85 nm, preferably ranging from 15 nm to 75 nm, and typically ranging from 20 nm to 65 nm,

[0228] (8) an optional LI layer having a physical thickness lower than or equal to 40 nm, in particular ranging from 2 nm to 35 nm, preferably ranging from 3 nm to 25 nm, and typically ranging from 5 nm to 15 nm,

[0229] (9) a HI layer (“outermost HI layer”) having a physical thickness lower than or equal to 100 nm, in particular ranging from 10 nm to 85 nm, preferably ranging from 15 nm to 75 nm, and typically ranging from 20 nm to 65 nm,

[0230] (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;

[0231] (11) the outermost LI layer having a physical thickness lower than or equal to 120 nm, in particular ranging from 60 nm to 110 nm, preferably ranging from 65 nm to 100 nm, and typically ranging from 70 nm to 90 nm.

[0232] B.3 Other functional layers

[0233] The antireflective coating may be deposited directly onto a bare substrate.

[0234] 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.

[0235] 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.

[0236] 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).

[0237] 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.

[0238] 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. Anti-abrasion and / or anti-scratch coating

[0239] The antireflective coating of the invention is preferably deposited onto an anti-abrasion and / or anti-scratch coating.

[0240] 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.

[0241] 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.

[0242] 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).

[0243] 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.

[0244] Primer coating

[0245] 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.

[0246] Preferred primer compositions are compositions based on polyurethanes and compositions based on latexes, especially polyurethane type latexes optionally containing polyester units.

[0247] 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.

[0248] Hydrophobic and / or oleophobic coating

[0249] 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. 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.

[0250] Electrochromic

[0251] 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.

[0252] 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.

[0253] Photochromic

[0254] 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.

[0255] 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.

[0256] The reflection of the lens can be especially conspicuous during the transition from dark state to clear state, causing a discrepancy between the residual color of the coating (for instance blue or purple) and the residual color of the photochromic lens (in general grey, brown, green). A desaturated AR coating according to the invention enables to minimize the discrepancy for all kinds of photochromic colors.

[0257] Blue cut

[0258] 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

[0259] T(A) : Transmittance (%)

[0260] 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).

[0261] B(A) : Blue radiation hazard function (ISO 8980-3: Annex B), much broader than the refined B’, proposed in the 1970s by ICNIRP.

[0262] 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).

[0263] 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.

[0264] Filtering in that range may also provide increased visual performance due to increased contrast sensitivity.

[0265] 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:

[0266] 2|®80(tens x LED emission%)

[0267] CutLED = 100 -

[0268] SSge 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. 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.

[0269] LED emission is defined in% in the Cut LED formula above.

[0270] C) Optical article

[0271] Generally, the optical article is an optical lens, especially an ophthalmic lens.

[0272] 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.

[0273] Especially, the rear main face of the substrate of the optical article may be coated with the AR coating according to examples 4 and 5 which has a low Ruv at an angle of incidence of 35°.

[0274] 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).

[0275] 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.

[0276] Preferably, the light absorption of the article coated according to the invention is lower than or equal to 1%.

[0277] According to an embodiment, the optical article may be a tinted optical article or a sunglass optical article, both comprising a dye and / or pigments, and 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, preferably on the front main surface, and being configured so as to fulfill said predetermined optical conditions, and especially front Rv lower than or equal to 0.6 % for front S*uv lower than or equal to 0.8, or front Rv lower than or equal to 0.3% for front S*uv lower than or equal to 1.2.

[0278] According to an embodiment, the optical article may be:

[0279] - 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% and preferably comprises, or - a blue cut optical article(such as defined in the document EP4297629) comprising a selective filter blocking, at least partially, blue light in a wavelength range chosen within the 400- 460 nm range; or

[0280] - a photochromic optical article or

[0281] - an electrochromic optical article.

[0282] Preferably, the optical article may be the clear or the blue cut optical article or the photochromic optical article or the electrochromic optical article and comprises the at least one multilayered antireflective coating according to the invention coated on the front main surface and on the rear main surface of the base element, said at least two multilayered antireflective coatings being configured so as to fulfill said predetermined optical conditions, and especially average Rv lower than or equal to 0.6 % for average S*uv lower than or equal to 0.8 or average Rv lower than or equal to 0.3% for average S*uv lower than or equal to 1 .2.

[0283] In general, the optical article is an optical lens, especially an ophthalmic lens.

[0284] D) Process

[0285] 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:

[0286] (a) providing the base element having a front main surface and a rear main surface ;

[0287] (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);

[0288] (c) depositing on the anti-abrasion and / or anti-scratch coating, the AR coating according to the invention.

[0289] 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.

[0290] 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.

[0291] In general, the AR coating and the other layers of the optical article are deposited by evaporation, optionally under ion beam assistance.

[0292] 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. E) Eyewear

[0293] The invention also relates to an eyewear comprising at least one optical article such as defined above, and preferably comprises an holding structure configured to hold the at least optical article facing a wearer’s eye.

[0294] Naturally, the various embodiments described above for the optical article also apply to this eyewear and will not be repeated below.

[0295] EXAMPLES

[0296] A) Characterization

[0297] 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) were carried out with a spectrophotometer. They are provided for an angle of incidence (also named hereafter “AOI” or 0) within the range from 0° to 45° for forward reflection. The method is similarly applied to the backward reflection for the optical and colorimetric characterization of the rear surface of the base element coated on its rear surface. Rear surface measurement, includes 35° backward reflection measurement. Mean light reflection factor Rv, hue angle h and chroma C* are defined in the international colorimetric CIE (L*, a*, b*) space. S*uv is defined in the international colorimetric CIE (L*, u*, v*) space. They are calculated considering the standard illuminant D65 or another illuminants such as illuminant LED2700K, and the standard observer 10° for h, C* and S*uv and the standard observer 2° for Rv.

[0298] B) Preparation of the optical articles

[0299] 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 rear main faces successively with a primer layer and an antiabrasion and anti-scratch coating (hard coat).

[0300] 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.

[0301] 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 around 2.6 micrometers.

[0302] The layers of the antireflection coating were deposited either on its front and back faces (lenses A to E) or only on its front main face (lenses 1 to 10) without heating of the substrates by vacuum evaporation (evaporation source: the electron gun).

[0303] Especially, the method comprises a surface activation step with an argon ion beam (3 A, 150 V) for 30s directly on the substrate, a deposition step of a HI layer (sheet (A), ZrC>2 or Ta2Os) at a rate of 1 nm / s, a deposition step of a SiC>2 layer (sheet (B)) at a rate of 1-2 nm / s, a deposition step of a HI layer (sheet (C), ZrC>2 or Ta2Os) at a rate of 1 nm / s, a surface activation step of this HI layer using an argon ion beam (1.5 A, 150 V) for 20s, a deposition step of a SiC>2 sub-layer at a rate of 3 nm / s optionally under an 02 atmosphere (at a pressure of about 1.6*10-4 mbar in AR examples 3 and 5 where 02 gas was supplied), a surface activation step of the sub-layer using an argon ion beam (1.5 A, 150 V) for 20s, a deposition step of a HI layer (ZrO2 or Ta2Os) at a rate of 2 nm / s, a deposition step of a LI layer (SiO2) at a rate of 1-3 nm / s, a deposition step of a HI layer (ZrO2 or Ta2Os) at a rate of 2 nm / s, a deposition step of a LI layer (SiO2) at a rate of 1-3 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: 1.8 A, 120 V), a deposition step of a LI layer (SiO2) at a rate of 2-4 nm / s, and lastly a deposition step of an Optool DSX® layer at a rate of 0.4 nm / s. Deposition step of HI layers of Ta2O5 was done with an oxygen ion assistance (ion gun: 1.5 A, 110 V).

[0304] 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).

[0305] 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) and / or a variable-incidence reflectance measurement system (Zeiss spectrometer MCS601).

[0306] C) Tested Lenses and results

[0307] C.1 Structures

[0308] The following structures have been exemplified:

[0309] Table 1

[0310] For lenses A to E, both the front main surface and the rear main surface of the substrate have been coated with the AR. Ex. A to Ex.E, respectively.

[0311] Table 2

[0312] Table 3

[0313] For lenses 1 to 10, only the front main surface has been coated with the AR Ex.1 to AR

[0314] Ex.10, respectively.

[0315] Table 4 For lenses 11 to 15, only the front main surface has been coated with the AR Ex.11 to AR Ex.15, respectively.

[0316] C.2 Results

[0317] Lenses A to E

[0318] Table 5 below illustrates the value of average Rv and average S*uv at an angle of incidence of 15° and the colorimetric coefficients a* et b* at an angle of incidence of 15°, 30° and 45° taking into account an illuminant D65 on the front main face of the exemplified lenses A to E (in reflection).

[0319] Table 5

[0320] Therefore, it has been observed for all Lenses A to E according to the invention that either the reflectance Rv (15°) on the front main face of the optical article is lower than or equal to 0.6% for a saturation value S*uv(15°) lower than or equal to 0.8 or the reflectance Rv (15°) on the front main face of the optical article is even lower than or equal to 0.3% for a saturation value S*uv(15°) lower than or equal to 1.2. Hence, the exemplified AR coating A to E according to the invention are able to provide a non-visible residual reflected color on the front main face of Lenses A to E, respectively. Indeed, the reflection Rv is so low, that the residual reflected color is not perceptible or hardly noticeable for an observer and in addition, the color of this residual reflection is extremely clear (i.e.: white) and thus imperceptible for an observer. Furthermore, whatever the angle of incidence, i.e.: 15°, 30° or 45°, the colorimetric coefficients a* and b* are very low and fall within the ranges a* < 3, especially - 1 .5 < a* < 0.5 and b* < 3, especially -7 < a* < 0.5. These colorimetric coefficients a* and b* are also illustrated on Fig.1 which shows the evolution in a* / b* map of the colorimetric coefficients a* and b* at angles of incidence of 15°, 30° and 45° of Lenses A to E (the start point of the arrow gives the value at 15°, the middle at 30° and the end - where is the arrow- at 45°). Lenses 1 to 10

[0321] Tables 6 and 7 below illustrate the value of Rv(front) and S*uv(front) at an angle of incidence of 15° and the colorimetric coefficients a*(front) et b*(front), the Chroma C*(front) at an angle of incidence of 15°, 30° and 45° taking into account an llluminant D65 on the front main face of the exemplified lenses 1 to10 (in reflection).

[0322] Table 6

[0323] Table 7

[0324] It can be observed from these Tables 6 and 7 and Fig. 4 that Lenses 1 to 10 according to the invention, have, in reflection on their front face, a very low reflectivity, while having excellent colorimetric properties and this whatever the angles of incidence. The AR coating appear for both observers and wearer almost non-visible and hence do not change the skin color or eyes of the wearer.

[0325] Lenses 11 to 15

[0326] Tables 8 below illustrates the value of Rv(front) and S*uv(front) at an angle of incidence of 15° or 35° and the colorimetric coefficients a*(front) et b*(front), the Chroma C*(front) at an angle of incidence of 15° and 35° taking into account an llluminant D65 on the front main face of the exemplified lenses 11 to15 (in reflection).

[0327] Table 8

Claims

1. 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 element, 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”, said optical article has, on its front main face, a front mean light reflection factor in the visible region, defined as Rv(front) and a front saturation value, defined as S*uv(front), on its rear main face, a rear mean light reflection factor in the visible region, defined as Rv(rear) and a rear saturation value, defined as S*uv(rear), an average of mean light reflection factors, defined as average Rv, and corresponding to (Rv(front) + Rv(rear)) / 2 and an average of saturation values, defined as average S*uv, corresponding to (S*uv(front) + S*uv(rear)) / 2, characterized in that the at least one multilayer antireflective coating is configured to provide to the optical article, in reflection, under the standard illuminant D65 and for an angle of incidence of 15° the following predetermined optical and colorimetric conditions: at least one of Rv(front), Rv(rear) and average Rv lower than or equal to 0.6 % for, respectively, S*uv(front), S*uv(rear) and average S*uv lower than or equal to 0.8, or at least one of Rv(front), Rv(rear) and average Rv lower than or equal to 0.3% for, respectively, S*uv(front), S*uv(rear) and average S*uv lower than or equal to 1 .2, said Rv(front) or Rv(frear) being as defined in the ISO 13666:1988 standard and measured in accordance with the ISO 8980-4: 2006, said S*uv(front) or S*uv(rear) being as defined in the CIELLIV color space.

2. The optical article according to claim 1 , wherein the at least one multilayer antireflective coating is configured so as to provide to the optical article, in reflection, under the standard illuminant D65 and for an angle of incidence of 15°, Rv(front) and Rv(rear) that fulfill said predetermined optical conditions:- Rv(front) and Rv(rear) are each lower than or equal to 0.6 % for S*uv(front) and S*uv(rear) being each lower than or equal to 0.8, or- Rv(front) and Rv(rear) are each lower than or equal to 0.3% for S*uv(front) and S*uv(rear) being each lower than or equal to 1 .2.

3. The optical article according to claim 1 or 2, wherein said optical article has, on its front main face, front colorimetric coefficients a*, b* and C*, defined respectively as a*(front), b*(front) and c* (front), on its rear main face, rear colorimetric coefficients a*, b* and C*, defined respectively asa*(rear), b*(rear) and c*(rear), said colorimetric coefficients a*, b* and C* being as defined in the CIE (1976) L*a*b* international colorimetric system taking the standard illuminant D65, and wherein, the at least one multilayer antireflective coating is configured so as to provide to the optical article, in reflection, under the standard illuminant D65:Rv(front) lower than or equal to 0.6 % for S*uv(front) lower than or equal to 0.8 or Rv(front) lower than or equal to 0.3 % for S*uv(front) lower than or equal to 1 .2 for an angle of incidence of 15° and a*(front) < 3 for b*(front) < 0 or -3 < a*(front) < 3 for 0 < b*(front) < 3 or C*(front) < 2 for b*(front) > 0, for all angles of incidence comprised between 0° and 45°, especially from 15° to 45°; orRv(rear) lower than or equal to 0.6 % for S*uv(rear) lower than or equal to 0.8 or Rv(rear) lower than or equal to 0.3 % for S*uv(rear) lower than or equal to 1.2 for an angle of incidence of 15° and a*(rear) < 3 for b*(rear) < 0 or -3 < a*(rear) < 3 for 0 < b*(rear) < 3 or C*(rear) < 2 for b*(rear) > 0, for all angles of incidence comprised between 0° and 45°, especially from 15° to 45°; or average Rv lower than or equal to 0.6 % for average S*uv lower than or equal to 0.8 or average Rv lower than or equal to 0.3 % for average S*uv lower than or equal to 1 .2 for an angle of incidence of 15° and a*(front) < 3 for b*(front) < 0 or -3 < a*(front) < 3 for 0 < b*(front) < 3 or C*(front) < 2 for b*(front) > 0, for all angles of incidence comprised between 0° and 45°, especially from 15° to 45°.

4. The optical article according to claim 3, wherein the at least one multilayer antireflective coating is configured so that:Rv(front) is lower than or equal to 0.6 % for S*uv(front) lower than or equal to 0.8 or Rv(front) is lower than or equal to 0.3 % for S*uv(front) lower than or equal to 1 .2 for an angle of incidence of 15° and a*(front) < 3 for b*(front) < 0 or -3 < a*(front) < 3 for 0 < b*(front) < 3 or C*(front) < 2 for b*(front) > 0, for all angles of incidence comprised between 0° and 45°, especially from 15° to 45°; andRv(rear) is lower than or equal to 0.6 % for S*uv(rear) lower than or equal to 0.8 orRv(rear) is lower than or equal to 0.3 % for S*uv(rear) lower than or equal to 1.2 for an angle of incidence of 15° and a*(rear) < 3 for b*(rear) < 0 or -3 < a*(rear) < 3 for 0 < b*(rear) < 3 or C*(rear) < 2 for b*(rear) > 0, for all angles of incidence comprised between 0° and 45°, especially from 15° to 45°.

5. The optical article according to any one of preceding claims, wherein the at least one multilayer antireflective coating is configured so that at least one of Rv(front), Rv(rear) and average Rv is lower than or equal to 0.55 % or preferably lower than 0.45 % for, respectively, S*uv(front), S*uv(rear) and average S*uv lower than or equal to 0.8, preferably lower than or equal to 0.75.

6. The optical article according to any one of preceding claims, wherein, by using an illumination LED 2700K instead of the standard illuminant D65 and an angle of incidence of 15°, the multilayer antireflective coating is configured so as to provide to the optical article the following predetermined optical conditions:- at least one of Rv(front), Rv(rear) and average Rv is lower than or equal to 0.6 % for, respectively, S*uv(front), S*uv(rear) and average S*uv lower than or equal to 0.8, or- at least one of Rv(front), Rv(rear) and average Rv is lower than or equal to 0.3% for, respectively, S*uv(front), S*uv(rear) and average S*uv lower than or equal to 1.2, preferably lower than or equal to 1.0; or- at least one of Rv(front), Rv(rear) and average Rv is lower than or equal to 0.4% for, respectively, S*uv(front), S*uv(rear) and average S*uv lower than or equal to 1 , preferably lower than or equal to 0.65.

7. The optical article according to any one of the preceding claims, wherein the at least one multilayer antireflective coating is configured so that the rear main surface of the optical article 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°.

8. The optical article according to any one of the preceding claims, wherein one of the LI layers of said at least one multilayer antireflective coating is a LI layer, defined as “thick LI layer”, which has a physical thickness higher than or equal to 100 nm, especially higher than or equal to 120 nm, preferably higher than or equal to 130 nm and typically higher than or equal to 140 nm, and is, starting from the substrate, the second LI layer among all the LI layers of the multilayer antireflective coating.

9. The optical article according to the preceding claim, wherein the ratio, RTI , defined asR TI= (sum of the physical thickness of the low refractive index layers of the antireflective coating and located above the thick LI layer in the direction moving away from the substrate) / (sumof the physical thickness of the high refractive index layers of the antireflective coating and located above the thick LI layer in the direction moving away from the substrate), is higher than or equal to 0.8, preferably higher than or equal to 0.7 and typically higher than or equal to 0.9, such as higher than or equal to 1 .0.

10. The optical article according to any one of the preceding claims, wherein the at least one multilayered antireflective coating comprises, in the direction moving away from the substrate:- a HI layer or HI sheet, which is in innermost position among all the HI layers of multilayered antireflective coating, named “innermost HI layer or innermost HI sheet”, which has a physical thickness of 50 nm or less, preferably of 40 nm or less, especially of 30 nm or less, preferably of 25 nm or less, in particular of 20 nm or less and which is in general the innermost layer among all the layers composing the multilayer antireflective coating- a LI layer or LI sheet, which is in innermost position among all the LI layers of the multilayered antireflective coating, named “innermost LI layer or innermost LI sheet”, which has a physical thickness of at least 10 nm, preferably of at least 20 nm, in particular of at least 30 nm, and typically of at least 40 nm and preferably lower than or equal to 100 nm, preferably lower than or equal to 90 nm, and typically lower than or equal to 80 nm; generally, the innermost HI layer is coated with the innermost LI layer, or inversely.

11. 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, both comprising a dye and / or pigments, and comprises one of the said at least one multilayered antireflective coating coated on the front main face or on the rear main surface of the base element, preferably on the front main surface, and being configured so as to fulfill said predetermined optical and colorimetric conditions, and especially front Rv lower than or equal to 0.6 % for front S*uv lower than or equal to 0.8, or front Rv lower than or equal to 0.3% for front S*uv lower than or equal to 1.2.

12. The optical article according to any one of the preceding claims, wherein the optical article comprises two of said at least one multilayered antireflective coatings, coated respectively on its the front main face and on its the rear main face, each multilayered antireflective coating being configured so as to fulfill said predetermined optical conditions, and especially average Rv lower than or equal to 0.6 % for average S*uv lower than or equal to 0.8, or average Rv lower than or equal to 0.3% for average S*uv lower than or equal to 1.2.

13. The optical article according to any one of the preceding claim, wherein the optical article:- 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.

14. The optical article according to any one of the preceding claims, wherein the optical article is an optical lens, especially an ophthalmic lens.

15. Eyewear comprising at least one optical article according to the proceeding claims.

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