Optical article comprising an antireflection coating having a very low reflection in the visible and ultraviolet range

文档序号：1435138 发布日期：2020-03-20 浏览：20次中文

阅读说明：本技术 包括在可见和紫外区内具有极低反射的减反射涂层的光学制品 (Optical article comprising an antireflection coating having a very low reflection in the visible and ultraviolet range ) 是由 I·博利沙科夫 H·莫里 X·丁于 2014-05-05 设计创作，主要内容包括：本发明涉及一种眼科镜片,该眼科镜片包括具有前主面和后主面的透明基底,这些主面中的至少一个涂覆有多层式减反射涂层,该多层式减反射涂层包括具有高于或等于1.55的折射率的至少一个高折射率层(HI)和具有低于1.55的折射率的至少一个低折射率层(LI)的堆叠体,其特征在于：所述至少一个高折射率层(HI)与所述至少一个低折射率层(LI)直接接触,形成双层,所述双层具有低于或等于60nm的物理厚度,所述双层在背离所述透明基底的方向上是在所述多层式减反射涂层中位于倒数第二位置处,对于在从20°至50°范围内的入射角,所述多层式减反射涂层具有低于5％的在280nm与380nm之间的平均反射系数R<Sub>UV</Sub>。(The invention relates to an ophthalmic lens comprising a transparent substrate having a front main face and a rear main face, at least one of these main faces being coated with a multilayered antireflective coating comprising a stack of at least one high refractive index layer (HI) having a refractive index higher than or equal to 1.55 and at least one low refractive index Layer (LI) having a refractive index lower than 1.55, characterized in that: the at least one high refractive index layer (HI) is in direct contact with the at least one low refractive index Layer (LI) forming a bilayer having a physical thickness lower than or equal to 60nm, the bilayer being in the multilayered antireflective coating in a direction away from the transparent substrateAt the penultimate position, said multilayered antireflective coating has an average reflection coefficient R between 280nm and 380nm lower than 5% for an angle of incidence in the range from 20 ° to 50 ° UV 。)

1. An ophthalmic lens comprising a transparent substrate having a front main face and a rear main face, at least one of these main faces being coated with a multilayered antireflective coating comprising a stack of at least one high refractive index layer (HI) having a refractive index higher than or equal to 1.55 and at least one low refractive index Layer (LI) having a refractive index lower than 1.55, characterized in that:

■ the at least one high refractive index layer (HI) and the at least one low refractive index Layer (LI) are adjacent, forming a bilayer,

■ the bilayer has a physical thickness of less than or equal to 60nm,

■ the bi-layer is located at a penultimate position in the multi-layer anti-reflective coating in a direction away from the transparent substrate, and

■, wherein the anti-reflective coating has a Δ E76 for angles of incidence of 15 ° and 45 ° defined by the colorimetric CIE L ＊ a ＊ b ＊, said Δ E76 being lower than or equal to 12.

2. The ophthalmic lens according to claim 1, wherein said multilayered antireflective coating has an average reflection coefficient R between 280nm and 380nm lower than 5% for an angle of incidence ranging from 20 ° to 50 °_UVWherein, in the step (A),

where R (λ) represents the spectral reflectance of the lens at a given wavelength, and W (λ) represents a weighting function equal to the product of the solar spectral irradiance Es (λ) and the efficiency versus spectral function S (λ).

3. The ophthalmic lens of claim 1 or 2, wherein the bilayer has a physical thickness of less than or equal to 30 nm.

4. Ophthalmic lens according to claim 1 or 2, wherein the high refractive index layer (HI) comprised in said bilayer has a physical thickness lower than or equal to 30nm, provided that the total physical thickness of the bilayer is lower than or equal to 60 nm.

5. The ophthalmic lens according to claim 4, wherein the high refractive index layer (HI) comprised in said bilayer has a physical thickness lower than or equal to 15 nm.

6. Ophthalmic lens according to claim 1 or 2, wherein the low refractive index Layer (LI) comprised in said bilayer has a physical thickness lower than or equal to 30nm, provided that the total physical thickness of the bilayer is lower than or equal to 60 nm.

7. Ophthalmic lens according to claim 6, wherein the low refractive index Layer (LI) comprised in said bilayer has a physical thickness lower than or equal to 15nm, provided that the total physical thickness of the bilayer is lower than or equal to 60 nm.

8. Ophthalmic lens according to claim 1 or 2, wherein the high refractive index layer (HI) comprised in said bilayer is a conductive layer.

9. The ophthalmic lens of claim 8, wherein the conductive layer comprises indium oxide, tin dioxide, zinc oxide, or mixtures thereof.

10. The ophthalmic lens of claim 8, wherein the conductive layer comprises indium tin oxide (In)₂O₃/SnO₂。

11. Ophthalmic lens according to claim 1 or 2, wherein the multilayered antireflective coating comprises alternating high refractive index layers (HI) and low refractive index Layers (LI) and has a number of layers lower than or equal to 10.

12. The ophthalmic lens according to claim 11, wherein the multilayered antireflective coating has a number of layers lower than or equal to 7.

13. An ophthalmic lens according to claim 1 or 2, wherein the outer layer, the layer furthest from the substrate, is a low refractive index layer.

14. The ophthalmic lens according to claim 13, wherein the outer layer is a monolayer and has a thickness of at most 100 nm.

15. The ophthalmic lens according to claim 13, wherein the outer layer is a monolayer and has a thickness between 20nm to 90 nm.

16. The ophthalmic lens according to claim 11, wherein the antireflective coating comprises, in a direction away from the substrate:

-one sub-layer having a physical thickness of from 100 to 300nm,

-a high refractive index layer (HI) having a physical thickness of from 8 to 25nm,

-a low refractive index layer (li) having a physical thickness of from 15 to 35nm,

-a high refractive index layer (HI) having a physical thickness higher than or equal to 75nm,

-a low refractive index layer of the bilayer having a physical thickness lower than or equal to 20 nm;

-a high refractive index layer of the bilayer having a physical thickness lower than or equal to 20nm

-the low refractive index outer layer having a physical thickness of from 55 to 95 nm.

17. The ophthalmic lens according to claim 16, wherein the antireflective coating comprises in a direction away from the substrate,

-one sub-layer having a physical thickness of from 120 to 180nm,

-a high refractive index layer (HI) having a physical thickness of from 10 to 20nm,

-a low refractive index layer (li) having a physical thickness of from 20 to 30nm,

-a high refractive index layer (HI) having a physical thickness of from 75 to 110nm,

-the low refractive index Layer (LI) having a physical thickness of from 4 to 12nm,

-the high refractive index layer (HI) having a physical thickness of from 3 to 12nm,

-the low refractive index outer layer having a physical thickness of from 65 to 90 nm.

18. The ophthalmic lens according to claim 11, wherein the antireflective coating comprises, in a direction away from the substrate:

-a multilayered sublayer comprising:

i) a low refractive index Layer (LI) having a physical thickness of from 15 to 80nm,

ii) a high refractive index layer (HI) having a physical thickness of from 5 to 50nm,

iii) a main layer having a physical thickness of from 100 to 300nm,

-a high refractive index layer (HI) having a physical thickness of from 8 to 25nm,

-a low refractive index layer (li) having a physical thickness of from 15 to 35nm,

-a high refractive index layer (HI) having a physical thickness higher than or equal to 75nm,

-a low refractive index layer of the bilayer having a physical thickness lower than or equal to 20 nm;

-a high refractive index layer of the bilayer having a physical thickness lower than or equal to 20nm, optionally comprising an antistatic layer;

-the low refractive index outer layer having a physical thickness of from 55 to 95 nm.

19. The ophthalmic lens according to claim 18, wherein the antireflective coating comprises in a direction away from the substrate,

-a multilayered sublayer comprising:

i) a low refractive index layer (li) having a physical thickness of from 20 to 50nm,

ii) a high refractive index layer (HI) having a physical thickness of from 6 to 25nm,

iii) a main layer having a physical thickness of from 100 to 300nm,

-a high refractive index layer (HI) having a physical thickness of from 8 to 25nm,

-a low refractive index layer (li) having a physical thickness of from 15 to 35nm,

-a high refractive index layer (HI) having a physical thickness higher than or equal to 75nm,

-a low refractive index layer of the bilayer having a physical thickness lower than or equal to 15 nm;

-a high refractive index layer of the bilayer having a physical thickness lower than or equal to 15nm, which may comprise an antistatic layer;

-the low refractive index outer layer having a physical thickness of from 55 to 95 nm.

20. Ophthalmic lens according to claim 1 or 2, wherein the rear main face and the front main face of the ophthalmic lens are coated with similar or different said multilayered antireflective coating.

21. The ophthalmic lens according to claim 1 or 2, wherein the antireflective coating has a Δ E76 defined by the color CIE L ＊ a ＊ b ＊ of lower than or equal to 12 for angles of incidence of 15 ° and 45 °.

Technical Field

The present invention relates to an optical article comprising an antireflection coating that substantially reduces reflection in both the UV and visible regions. The optical article may in particular be an ophthalmic lens, in particular an ophthalmic lens.

Background

Antireflection coatings generally consist of a multilayer comprising thin interference layers, which is generally based on the alternation of layers of dielectric material having a high refractive index and of dielectric material having a low refractive index. When deposited on a transparent substrate, the function of such coatings is to reduce their light reflection and thus increase their light transmission. The substrate thus coated will therefore have its transmitted/reflected light ratio increased, thereby improving the visibility of objects placed behind it. When seeking to obtain maximum antireflection effects, it is then preferable to provide both faces (front and rear) of the substrate with a coating of this type.

Such antireflective coatings are commonly used in the ophthalmic field. Thus, conventional antireflective coatings are designed and optimized to reduce the reflection of the visible region (typically in the spectral range from 380 to 780nm) on the lens surface. In general, the average light reflection coefficient R in the visible region on the front and/or rear face of an ophthalmic lens_vIs between 1.5% and 2.5%.

Some of these antireflective coatings may also be designed and optimized to reduce reflection on the lens surface in the UVA band from 315 to 400nm and/or the UVB band from 280 to 315 nm. These UVA and UVB bands are indeed particularly harmful to the retina.

For conventional anti-reflective lenses, the average reflection in the UVA and UVB region can thus reach high levels (up to 60%). In one aspect, with respect to non-solar antireflective articles that have been marketed by most manufacturers in recent years, the UV average reflection range is from 10% to 25% for incident angles from 30 ° to 45 °. There are no problems with the lens front face since most of the UV radiation coming from the front face of the wearer and that can reach the wearer's eye (normal incidence, 0 to 15 °) is generally absorbed by the ophthalmic lens substrate. Better protection against UV radiation transmission can be obtained by sunglass lenses which are studied and designed to reduce the visible spectral luminosity, to absorb UVB completely and to absorb UVA completely or partially.

On the other hand, if the lenses are not provided with an antireflective coating that is effective in the ultraviolet region, UV radiation generated by a light source located behind the wearer may reflect behind the lenses and reach the wearer's eyes, thereby potentially affecting the wearer's health. This phenomenon is exacerbated by the trend toward fashion sunglasses with high diameters that increase the risk of stray reflections entering the eye.

It is recognised that the light rays that can be reflected behind the lens and reach the eye of the wearer have a narrow range of incidence angles, ranging from 30 ° to 45 ° (oblique incidence).

There is currently no standard concerning the reflection of UV radiation from behind.

Furthermore, optimizing the antireflective performance over the entire ultraviolet range generally shows a disadvantage for antireflective performance in the visible range. In contrast, optimizing only the antireflection performance in the visible region does not ensure that satisfactory antireflection characteristics can be obtained in the ultraviolet region.

There are many patented treatments for making antireflective coatings that are effective in the visible region and, at the same time, ultimately reduce UV radiation reflection.

For example, application WO 2012/076714 describes an ophthalmic lens having a very low value of reflectivity in the visible region. This ophthalmic lens comprises a substrate having a front main face and a rear main face coated with a multilayered antireflective coating comprising a stack of at least one layer having a refractive index higher than 1.6 and at least one layer having a refractive index lower than 1.5. The ophthalmic lens is characterized in that:

-an average reflection coefficient R on said rear face in the visibility region_mLess than or equal to 1.15%,

-an average light reflection coefficient R on said rear face in the visible region_vLess than or equal to 1%,

-an average reflection coefficient R on said rear face between 280nm and 380nm weighted by a function W (λ) defined in the ISO13666:1998 standard for an angle of incidence of 30 ° and for an angle of incidence of 45 °_UVLess than 5 percent of the total weight of the composition,

the multilayered antireflective coating comprises a plurality of layers higher than or equal to 3 and lower than or equal to 7, preferably lower than or equal to 6, more preferably lower than or equal to 5 layers,

the multilayered antireflective coating does not comprise any conductive layer based on indium oxide having a thickness higher than or equal to 20nm, and

-the outer antireflection coating layer is a silica-based layer.

The antireflection coating described in this application is very effective in the visible region (R)_vLess than or equal to 1%) while at the same time being able to significantly reduce UVA radiation reflections, in particular ultraviolet a rays and ultraviolet B rays. However, it would be sensible to improve its robustness and its aesthetic appearance, especially at oblique incidence.

The term "robustness" of a lens in the present invention is defined as the ability of the lens to resist changes other than those caused by its manufacturing process. These variations depend, for example, on the type of substrate used, the settings of the production machine (temperature regime, appropriate times, settings of the electron gun) and/or the mode of use thereof, said production machine being replaced by another production machine.

In fact, when multilayer antireflective coatings are manufactured on an industrial scale, some thickness variation of the layers usually occurs. These variations result in different reflective properties and, in particular, different perceived residual reflection colors of the multilayered antireflective coating. If the perceived residual reflected colors of the antireflection coatings of the two lenses are different, the lenses will appear different and will not be able to be associated in pairs.

Furthermore, depending on the curvature and the value of incidence (angle θ) of the lenses, the residual reflection color of the multilayered antireflective coating of each lens appears to be non-uniform in color over the entire surface of the lens ("discoloration effect"). The observer can observe different residual reflection colors between the right and left portions of the lens, such as a color gradation of different hue "h" (different colors, e.g. from blue to red) or a color gradation of different color intensity (e.g. from saturated to less saturated, or vice versa), depending on the angle of incidence θ. It would therefore be desirable to improve the aesthetic appearance of such lenses by obtaining, for example, a uniform perceived residual reflected color of the lens surface for an observer viewing the lens wearer.

Most antireflective coatings developed to date are optimized to minimize light reflection at normal incidence without regard to the optical and aesthetic appearance and/or the robustness characteristics of the multilayered antireflective coating visible at oblique incidence.

Document JP 2011-. In particular, the antireflection film comprises 11 layers having successively lower and higher refractive indices (i.e. alternately SiO)₂And TiO₂) And having the following thicknesses in the direction away from the substrate:

1)SiO₂layer (b): 10-31 nm;

2)TiO₂layer (b): 4-34 nm;

3)SiO₂layer (b): 18-45 nm;

4)TiO₂layer (b): 102-117 nm;

5)SiO₂layer (b): 7-27 nm;

6)TiO₂layer (b): 2-18 nm;

7)SiO₂layer (b): 153-180 nm;

8)TiO₂layer (b): 29-41 nm;

9)SiO₂layer (b): 2-13 nm;

10)TiO₂layer (b): 53-66 nm;

11)SiO₂layer (b): 83-95 nm.

However, this document does not mention the reflectance of such an antireflection film in the UV region, particularly in the UVA band (i.e., it ranges from 315nm to 380 nm).

Therefore, there remains a need to provide novel antireflective coatings having very good antireflective properties in the visible as well as in the UV region, especially in UVA, while having robust properties and aesthetic appearance regardless of the angle of incidence compared to prior art antireflective coatings.

Disclosure of Invention

It is therefore an object of the present invention to solve the above drawbacks by seeking to develop a transparent optical article, in particular an ophthalmic lens, comprising a substrate in the form of an inorganic or organic glass, comprising at least one antireflection coating having very good antireflection properties in the UV region and in the visible region, while guaranteeing both good aesthetics (regardless of the angle of incidence) and high robustness, and doing so without affecting the economic and/or industrial feasibility of its manufacture.

In another aspect of the invention, the antireflective coating is capable of reducing UV radiation reflection, particularly ultraviolet a rays and ultraviolet B rays, as compared to a bare substrate or to a substrate comprising a conventional antireflective coating.

The present invention therefore relates to an optical article, preferably an ophthalmic lens, comprising an ophthalmic lens comprising a transparent substrate having a front main face and a rear main face, at least one of the main faces being coated with a multilayered antireflective coating comprising a stack of at least one high refractive index layer (HI) having a refractive index higher than or equal to 1.55 and at least one low refractive index Layer (LI) having a refractive index lower than 1.55, characterized in that:

■ the at least one high refractive index layer (HI) and the at least one low refractive index Layer (LI) are adjacent, forming a bilayer,

■ the bilayer has a physical thickness of less than or equal to 60nm, preferably less than or equal to 30nm

■ the bi-layer is located at a penultimate position in the multi-layer anti-reflective coating in a direction away from the transparent substrate,

■ has, for an angle of incidence in the range from 20 ° to 50 °, an average reflection coefficient R between 280nm and 380nm weighted by a function W (λ) defined in the ISO13666:1998 standard, lower than 5%_UV。

The applicant has found that the low thickness of the two adjacent layers, respectively having a high and a low refractive index, combined in their position in the antireflection stack, makes it possible to obtain an antireflection effect within a wide reflection band (UVA, UVB and visible), with a neutral hue in transmission and an attractive appearance of reflection (whatever the angle of incidence at which the substrate thus coated is observed).

Furthermore, it was unexpectedly found that the ophthalmic lenses according to the invention exhibit good robustness characteristics.

Drawings

The invention will be described in more detail by reference to the accompanying drawings, in which:

fig. 1 shows the theta reflection (R,%) on the anterior surface of some lenses prepared in the examples of the present application (examples 1 and 7) and for a spectral function W (λ) at an angle of incidence of 15 ° as a function of wavelength in the UVA (315 to 400nm) band, the UVB (280 to 315nm) band and in the visible region (380 to 780 nm). In particular, lens 1 was prepared according to the invention and lens 7 was a comparative example according to the prior art; and is

Fig. 2 is a table showing the optical characteristics of the lenses 1 to 7 described above.

Detailed Description

The terms "comprising" (and any grammatical variations thereof, such as "comprises" and "comprising)", "having" (and any grammatical variations thereof, such as "has" and "has)", "containing" (and any grammatical variations thereof, such as "contains" and "containing)", and "including" (and any grammatical variations 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, components or groups thereof. Thus, 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.

As used herein, unless otherwise indicated, all numbers or expressions referring to quantities of ingredients, ranges, reaction conditions, and the like are to be understood as modified in all instances by the term "about.

Further, unless otherwise indicated, according to the present invention, an indication of an interval of values "from X to Y" or "between X and Y" is intended to include the values of X and Y.

In the present application, when an optical article comprises one or more coatings on its surface, the expression "depositing a layer or coating onto the article" is intended to mean depositing a layer or coating onto the outer (exposed) surface of the outer coating of the article, i.e. the coating which is furthest from the substrate.

The coating to be "on" or deposited onto a substrate is defined as a coating that is (i) placed over the substrate; (ii) not necessarily in contact with the substrate, i.e. one or more intermediate coatings may be arranged between the substrate and the coating in question; and (iii) does not necessarily completely cover the substrate.

In a preferred embodiment, the coating on or deposited onto the substrate is in direct contact with this substrate.

When "layer 1 is located below layer 2," it is intended to mean that layer 2 is further from the substrate than layer 1.

As used herein, the back (or interior) face of the substrate is intended to refer to the face closest to the wearer's eye when the article is used. It is generally concave. In contrast, the front face of the substrate is the face that is furthest from the wearer's eye when the article is in use. It is usually a convex surface.

The optical article prepared according to the present invention is a transparent optical article, preferably a lens or lens blank, and more preferably an ophthalmic lens or lens blank. The method of the present invention may be used to coat a convex major side (front side), a concave major side (back side), or both sides of an optical article.

In summary, the antireflective coating (which will be referred to as "antireflective coating") of the optical article according to the invention may be deposited onto any substrate, and preferably onto an organic lens substrate (e.g. a thermoplastic or thermoset plastic material).

The thermoplastic may be selected, for example, from: a polyamide; a polyimide; polysulfones; polycarbonates and copolymers thereof; poly (ethylene terephthalate) and polymethyl methacrylate (PMMA).

The thermosetting material may be selected, for example, from: cyclic olefin copolymers such as ethylene/norbornene or ethylene/cyclopentadiene copolymers; homopolymers and copolymers of allyl carbonate of linear or branched aliphatic or aromatic polyols, such as homopolymers of diethylene glycol bis (allyl carbonate); homopolymers and copolymers of (meth) acrylic acid and its esters, which may be derived from bisphenol a; polymers and copolymers of thio (meth) acrylic acid and esters thereof, polymers and copolymers of allyl esters which may be derived from bisphenol a or phthalic acid and allyl aromatics such as styrene, polymers and copolymers of urethanes and thiourethanes, polymers and copolymers of epoxy resins, and polymers and copolymers of sulfides, disulfides and episulfides, and combinations thereof.

As used herein, (co) polymer is intended to mean a copolymer or a polymer. As used herein, (meth) acrylate is intended to mean acrylate or methacrylate. As used herein, Polycarbonate (PC) is intended to mean homopolycarbonates or copolycarbonates and block copolycarbonates.

Before the deposition of the antireflective coating on the optionally coated substrate (for example with an abrasion-resistant and/or scratch-resistant coating or with a sublayer), the surface of said optionally coated substrate is generally subjected to a physical or chemical surface activation treatment in order to enhance the adhesion of the antireflective coating. This pretreatment is usually carried out under vacuum. It may be bombardment with energetic and/or reactive species, for example with ion beams ("ion pre-clean" or "IPC") or with electron beams, corona discharge treatment, ion spallation treatment, uv treatment or plasma-mediated treatment under vacuum (typically using oxygen or argon plasma). It may also be an acid or base treatment and/or a solvent-based treatment (water, hydrogen peroxide or any organic solvent).

As previously mentioned, the ophthalmic lens according to the invention comprises a transparent substrate having a front main face and a rear main face, at least one of these main faces being coated with a multilayered antireflective coating comprising a stack of at least one high refractive index layer (HI) having a refractive index higher than or equal to 1.55 and at least one low refractive index Layer (LI) having a refractive index lower than 1.55, characterized in that:

■ the at least one high refractive index layer (HI) and the at least one low refractive index Layer (LI) are adjacent, forming a bilayer,

■ the bilayer has a physical thickness of less than or equal to 60nm, preferably less than or equal to 30nm,

■ the bi-layer is located at a penultimate position in the multi-layer anti-reflective coating in a direction away from the transparent substrate,

■ has, for angles of incidence in the range from 20 ° to 50 °, an average reflection coefficient R between 280nm and 380nm weighted by a function W (λ) defined in the ISO13666:1998 standard, lower than 5%, preferably lower than 4%, ideally lower than 3.5%_UV。

In particular, the high refractive index layer (HI) comprised in the bilayer preferably has a physical thickness lower than or equal to 30nm, preferably lower than or equal to 20nm, more preferably lower than or equal to 15nm, in particular lower than or equal to 10nm and ideally lower than or equal to 9nm, provided that the total physical thickness of the bilayer is lower than or equal to 60nm, preferably lower than or equal to 30 nm.

In addition, according to the invention, the low refractive index Layer (LI) included in the bilayer preferably has a physical thickness lower than or equal to 30nm, preferably lower than or equal to 20nm, more preferably lower than or equal to 15nm, in particular lower than or equal to 10nm and ideally lower than or equal to 9nm, provided that the total physical thickness of the bilayer is lower than or equal to 60nm, preferably lower than or equal to 30 nm.

Generally and as will be explained below, the last layer, also called "outer layer", is a low refractive index layer, for example made of SiO₂And (4) preparing. The term "outer layer" is understood to mean either a single layer or a superposition of layers, in which each of them satisfies the indicated refractive index, and in which the sum of their geometric thicknesses also maintains the values indicated for the layer in question. For example, the outer layer may be made of two layers of SiO₂Made of, having the same or very close refractive index, or one may be made of SiO₂And the other one made of a mixture of silica and alumina, in particular silica doped with alumina, provided that they both have a low refractive index.

Furthermore, any layer having a thickness below 1nm will not be considered when counting the number of layers in the antireflective coating.

All thicknesses disclosed in this application relate to physical thicknesses unless otherwise indicated.

According to the invention, the "angle of incidence (symbol θ)" is the angle formed by a light ray incident on the surface of an ophthalmic lens and the surface normal at the point of incidence the light ray is a light source, for example, luminescent, such as the standard light source d65 as defined in international color CIE L ＊ a ＊ b ＊.

In the present application, weighted by a W (lambda) function defined according to the ISO13666:1998 standard and denoted R_UVThe average reflection coefficient between 280nm and 380nm can be defined by the following relation:

The spectral function W (λ) enabling the calculation of the ultraviolet radiation transmission coefficient is defined according to the ISO13666:1998 standard. This makes it possible to express to the wearer the ultraviolet solar radiation distribution modulated by the relative spectral efficiency of this radiation, since both the solar spectral energy Es (λ) (overall emitting less UVB-rays than UVA-rays) and the spectral efficiency S (λ) (UVB-rays are more harmful than UVA-rays) are taken into account.

According to one embodiment of the invention, the antireflective coating deposited onto at least one of the main surfaces of the transparent substrate is such that:

-the chromaticity C ＊ is low and equal to or lower than 13, preferably 10, and/or according to the international colorimetric CIE L ＊ a ＊ b ＊ for an angle of incidence θ of 15 ° and

-the hue (h) ranges from 250 to 330 °, preferably from 260 to 320 °, more preferably from 260 to 305 °, and/or according to the International colorimetric CIE L ＊ a ＊ b ＊ for an angle of incidence θ less than or equal to 35 °, preferably less than or equal to 30 ° and typically less than or equal to 15 °

- Δ E76 of the antireflection coating for angles of incidence of 15 ° and 45 ° defined by the colorimetric CIE L ＊ a ＊ b ＊ is lower than or equal to 12, preferably lower than or equal to 9.

Thus, the antireflective coating of the present invention exhibits a smooth perceived residual color change as a function of the angle of incidence θ.

The colorimetric coefficients of the optical article of the present invention in the international colorimetric system CIE L ＊ a ＊ b ＊ are calculated between 280 and 780nm taking into account the standard illuminant D65 and the observer (angle of 10 °).

This international colorimetric system enables, inter alia, the determination of the color change CIE. DELTA. E76. this parameter is defined by the following formula according to the "CIE 1976L ＊ a ＊ b ＊ color space standard:

wherein:

L₁、a₁、b₁which are coordinates in the CIE Lab color space of the first colors to be compared and

L₂、a₂、b₂is the coordinate of the second color to be compared (when Δ E76<2, this color difference is imperceptible to human vision).

As will be illustrated in the following examples, the hue h of the antireflection coating is substantially constant, i.e. typically between 250 and 330, for incident angles varying from 15 to 45, in fact, the perceived residual reflection color is "the same" for an observer with normal vision when the incident angle varies from 0 to 30, when the hue of the antireflection coating starts to vary for incident angles higher than 30, the chroma C ＊ is very low (lower than or equal to 8), i.e. the perceived residual reflection color is so light that the residual reflection color is not or hardly visible to the observer.

Furthermore, the antireflective coating according to the invention is designed in particular to have good antireflective properties in the visible region and/or to minimize reflection of ultraviolet radiation (with an angle of incidence on the lens ranging in particular from 30 ° to 45 °) towards the eye, and its preferred characteristics are described below.

Preferably, the average light reflection coefficient R of the ophthalmic lens in the visible region for at least one angle of incidence smaller than 35 °_vLess than or equal to 2.0%, preferably equal to or less than 1.5%, more preferably equal to or less than 1.0%.

Within the meaning of the present invention, the "average light reflection coefficient", denoted as R_vSuch as defined in the ISO13666:1998 standard, and according to ISO8980-4, i.e., this is a weighted spectral reflectance average over the entire visible spectrum between 380 and 780 nm. R_vIt is usually measured for incidence angles below 17 °, typically 15 °, but can be evaluated for any incidence angle.

In the present application, the "average reflection coefficient" is denoted as R_mIs such as defined in the ISO13666:1998 standard and is measured according to the ISO 8980-4 standard, i.e. this is the (unweighted) spectral reflection average over the entire visible spectrum between 400 and 700 nm. R_mIt is usually measured for incidence angles below 17 °, typically 15 °, but can be evaluated for any incidence angle.

In one embodiment, the multilayered antireflective coating preferably has an average reflection coefficient R in the visible range of less than or equal to 1, 15%, preferably less than or equal to 1%, more preferably less than or equal to 0.92%, for angles of incidence less than or equal to 35 ° and typically less than or equal to 15 °_m。

In another embodiment, the multilayered antireflective coating has an average reflection coefficient R between 280nm and 380nm weighted by a function W (λ) defined in the ISO13666:1998 standard, lower than or equal to 6%, preferably lower than or equal to 5%, more preferably lower than or equal to 4%, for an angle of incidence in the range of 15 ° to 45 °, preferably 30 ° to 45 °_UV。

According to the invention, the high refractive index layer (HI) comprised in the bilayer is typically a conductive layer. For example, the conductive layer includes indium oxide, tin dioxide (also referred to as tin oxide, SnO)₂) Zinc oxide or mixtures thereof. A preferred conductive layer comprises tin dioxide.

Generally, the multilayered antireflective coating comprises alternately high refractive index layers (HI) and low refractive index Layers (LI) and has a number of layers lower than or equal to 10, preferably lower than or equal to 8 and in particular lower than or equal to 7.

More preferably, it comprises at least two, preferably three layers with a low refractive index (LI) and at least two, preferably three layers with a high refractive index (HI). It is here a simple stack, since the total number of layers in the antireflection coating is higher than or equal to 4, and lower than or equal to 7, more preferably lower than or equal to 6, and most preferably equal to 6 layers.

Typically, the outer layer of the antireflective coating, which is the layer furthest from the substrate, is a low refractive index layer.

In particular, the outer layer is a monolayer and has a thickness of at most 100nm, preferably between 20 and 90nm and in particular from 45 to 80 nm.

The HI and LI layers need not alternate with each other in the stack, although they may also alternate according to one or more of the described embodiments of the invention. Two HI layers (or more) may be deposited on top of each other, and two LI layers (or more) may also be deposited on top of each other.

In the present application, a layer of an antireflection coating is said to have a high refractive index (HI) when its refractive index is higher than or equal to 1.55, preferably higher than or equal to 1.6, even more preferably higher than or equal to 1.7, even more preferably higher than or equal to 1.8 and most preferably higher than or equal to 1.9. The HI layer preferably has a refractive index below 2.1. When one layer of the antireflective coating has a refractive index lower than 1.55, preferably lower than 1.50, more preferably lower than or equal to 1.48, it is called a low refractive index Layer (LI). The LI layer preferably has a refractive index higher than 1.1.

The refractive indices mentioned in this application are expressed at a wavelength of 550nm at 25 ℃ unless otherwise specified.

The HI layer is a conventional high refractive index layer well known in the art. It typically includes one or more metal oxides such as, but not limited to: zirconium oxide (ZrO)₂) Titanium dioxide (TiO)₂) Alumina (Al)₂O₃) Tantalum pentoxide (Ta)₂O₅) Neodymium oxide (Nd)₂O₅) Praseodymium oxide (Pr)₂O₃) Praseodymium titanate (PrTiO)₃) Lanthanum oxide (La)₂O₃) Niobium oxide (Nb)₂O₅) Yttrium oxide (Y)₂O₃). Optionally, the HI layer may further contain silicon dioxide or other materials with a low refractive index, as long as they have a refractive index higher than or equal to 1.55 as indicated aboveRefractive index. Preferred materials include TiO₂、PrTiO₃、ZrO₂、Al₂O₃、Y₂O₃And mixtures thereof.

LI layers are also well known and may include, but are not limited to, SiO₂Or a mixture of silica and alumina (especially silica doped with alumina) which helps to increase the heat resistance of the antireflective coating. The LI layer is preferably a layer comprising at least 80% by weight of silica, more preferably at least 90% by weight of silica, and even more preferably a layer of silica, relative to the total weight of the layer. Preferably, the LI layer in the antireflective coating is not MgF₂And (3) a layer.

Optionally, the LI layer may further contain a material having a high refractive index, as long as the refractive index of the resulting layer is below 1.55.

When used, comprises SiO₂With Al₂O₃With respect to the SiO in the layer of LI of the mixture of (1)₂+Al₂O₃The total weight preferably comprises from 1% to 10%, more preferably from 1% to 8% and even more preferably from 1% to 5% by weight of Al₂O₃。

For example, doping with 4% by weight or less of Al may be employed₂O₃SiO of (2)₂Or doped with 8% Al₂O₃SiO of (2)₂. Commercially available SiO can be used₂/Al₂O₃Mixtures, e.g. sold by the company Umicorematerials AG company

(refractive index n. 1.48-1.50 at 550 nm), or sold by Merck KGaA company, Germany

(refractive index n 1.48 at 500 nm).

The outer layer of the antireflection coating, in particular the layer based on silica, preferably comprises at least 80% by weight of silica, more preferably at least 90% by weight of silica (for example a layer of silica doped with alumina), and even more preferably a layer of silica, relative to the total weight of the layer.

In one embodiment of the invention, the antireflective coating is deposited onto a sub-layer (the layer of the antireflective coating closest to the substrate, noted UL).

As used herein, an antireflective coating sublayer or adhesion layer is intended to refer to a relatively thick coating used to enhance the mechanical properties of the coating such as abrasion and/or scratch resistance and/or to enhance its adhesion to a substrate or underlying coating.

If the sub-layer is deposited directly onto the substrate, it generally does not participate in the anti-reflection optical activity, due to its relatively high thickness, especially when it has a refractive index close to that of the underlying coating (typically an abrasion and scratch resistant coating) or substrate.

The sub-layer should have a thickness sufficient to promote the abrasion resistance of the antireflection coating, but preferably not so great as to cause light absorption (depending on the nature of the sub-layer, the relative transmission coefficient τ can be reduced significantly_v). Its thickness is typically below 300nm, more preferably below 200nm, and typically above 90nm, more preferably above 100 nm.

The sub-layer preferably comprises a SiO-based material₂Preferably at least 80% by weight of silica, more preferably at least 90% by weight of silica, and even more preferably a layer of silica, relative to the total weight of the layer. The thickness of such a silicon dioxide based layer is typically below 300nm, more preferably below 200nm, and typically above 90nm, more preferably above 100 nm.

In another embodiment, the SiO-based₂Is a silica layer doped with alumina in an amount as defined above, preferably comprising a silica layer doped with alumina.

In a specific embodiment, the sub-layer comprises a layer of SiO 2.

Preferably a monolayer type of sub-layer will be used. However, the sub-layer may be laminated (multilayered), especially when the sub-layer and the underlying coating (or substrate if the sub-layer is deposited directly onto the substrate) have substantially different refractive indices. This applies in particular when the base coating (generally an abrasion-resistant coating and/or a scratch-resistant coating) or the substrate has a high refractive index, i.e. a refractive index higher than or equal to 1.55, preferably higher than or equal to 1.57.

In this case, in addition to the 90-300nm thick layer (referred to as the main layer), the sublayer may comprise preferably at most three additional layers, more preferably at most two additional layers, which are interleaved between the optionally coated substrate and the 90-300nm thick layer (typically a silica-based layer). These additional layers are preferably thin layers whose function is to limit reflection (as the case may be) at the sublayer/undercoat layer interface or the sublayer/substrate interface.

In addition to the main layer, the multilayered sub-layer preferably comprises a layer having a high refractive index and having a thickness lower than or equal to 80nm, more preferably lower than or equal to 50nm and most preferably lower than or equal to 30 nm. The layer having a high refractive index is in direct contact with the substrate having a high refractive index or the underlying coating having a high refractive index (as the case may be). Of course, this embodiment can be used even if the substrate (or undercoat) has a refractive index below 1.55.

As an alternative, the sub-layer comprises a material based on SiO, in addition to the main layer and the previously mentioned layer with a high refractive index₂A layer of a material according to (i.e. preferably comprising at least 80% by weight of silicon dioxide) having a refractive index lower than or equal to 1.55, preferably lower than or equal to 1.52, more preferably lower than or equal to 1.50 and having a thickness lower than or equal to 80nm, more preferably lower than or equal to 50nm and even more preferably lower than or equal to 30nm, said layer having a high refractive index being deposited onto the layer. Typically, in this case, the sub-layer comprises 37nm thick SiO deposited in this order onto an optionally coated substrate₂Layer, 7.6nm thick ZrO₂Or Ta₂O₅Layer and thereafter of 152nm SiO₂The sub-layer main layer is formed.

The optical article of the present invention can be made antistatic, i.e., not retaining and/or developing substantial static charges, by incorporating at least one charge dissipating conductive layer into the stack present at the surface of the article.

According to one embodiment of the invention, the antireflection coating comprises, in a direction away from the substrate:

-one sub-layer having a physical thickness of from 100 to 300nm,

-a high refractive index layer (HI) having a physical thickness of from 8 to 25nm,

-a low refractive index layer (li) having a physical thickness of from 15 to 35nm,

-a high refractive index layer (HI) having a physical thickness higher than or equal to 75nm,

-a low refractive index layer of the bilayer having a physical thickness lower than or equal to 20nm, preferably 15 nm;

-a high refractive index layer of the bilayer having a physical thickness lower than or equal to 20nm, preferably 15nm, which may comprise an antistatic layer;

-the low refractive index outer layer having a physical thickness of from 55 to 95 nm.

In particular, the antireflective coating comprises, in a direction away from the substrate,

-one sub-layer having a physical thickness of from 120 to 180nm,

-a high refractive index layer (HI) having a physical thickness of from 10 to 20nm,

-a low refractive index layer (li) having a physical thickness of from 20 to 30nm,

-a high refractive index layer (HI) having a physical thickness of from 75 to 110nm,

-the low refractive index Layer (LI) having a physical thickness of from 4 to 12nm,

-the high refractive index layer (HI) having a physical thickness of from 3 to 12nm, which may be an antistatic layer;

-the low refractive index outer layer having a physical thickness of from 65 to 90 nm.

When depositing the multilayered sub-layer, the anti-reflective coating may comprise, in a direction away from the substrate,

-a multilayered sublayer comprising:

i) a low refractive index layer (li) having a physical thickness of from 15 to 80nm,