Lenses having surface microstructures encapsulated by a thick hard coat of low refractive index

Abstract

The present invention relates to an optical article comprising a base lens substrate having at least one or more optical elements, such as microlenses or Fresnel structures, protruding from its surface, and a hard coat coating encapsulating each optical element. More specifically, the present invention relates to an optical article comprising a base lens substrate having opposing first and second lens surfaces, opposing first and second protective surfaces, a protective layer having a maximum thickness measured orthogonal to the first protective surface between the first and second protective surfaces, the first protective surface being disposed on the second lens surface, and at least one or more optical elements, each defining a portion of one of the first protective surface and the second lens surface, the at least one optical element having a maximum height measured orthogonal to the second lens surface carrying the optical element that is 0.1 millimeters (mm) or less and a diameter that is 2.0 mm or less, the protective layer being composed of a crosslinked matrix and nanoparticles, and the refractive index n of the protective layer being 0.1 mm or less. c is the refractive index n of at least one or each optical element m lower, thereby the difference n m -n c is greater than 0.045, preferably greater than 0.10, or even greater than 0.15, and the maximum thickness of the protective layer is at least twice, preferably at least five times, the maximum height of the or each optical element. The present invention also relates to a method for forming such an optical article, typically comprising an inkjet step.

Description

[Technical field]

[0001] The present invention relates to optical articles comprising a base lens substrate having at least one optical element, such as a microlens, Fresnel structure, or a plurality of optical elements protruding from a surface thereof, and methods of forming such optical articles. [Background technology]

[0002] Optical articles such as lenses generally comprise a base lens substrate shaped to provide a desired optical power and an anti-abrasion coating that covers at least one surface of the base lens substrate to prevent it from being damaged by abrasion.

[0003] According to a preferred embodiment, the anti-abrasion coating, also known as a hard coating, has a two-layer structure and provides a hardness gradient from the base lens substrate to the free surface of the anti-abrasion coating. The upper layer of the coating defines the hardest part of the coating at the free surface, allowing protection against thin particles and thin scratches, while the lower layer of the coating defines the lower hardness part below, absorbing the impact provided by larger particles and preventing the formation of larger scratches. It also provides a transition with the hardness of the base lens substrate, preventing the formation of cracks at the interface between the substrate and the anti-abrasion coating.

[0004] It has been found that in some applications it is desirable to provide a plurality of optical elements, such as microlenses, on a base lens substrate to provide a local variation in the refractive power of the optical article. For example, from US 2017 / 0131567 A1, a lens is known which comprises a plurality of microlenses formed on the surface of the lens, the local variation in refractive power provided by the microlenses making it possible to prevent or slow the progression of myopia.

[0005] From document WO 2016 / 168746, lenses are also known which have a first refractive power, which lens comprises an array of microlenses having a second refractive power, the microlenses making it possible to enhance the correction provided by the lens even when the curvature of the lens is limited, or to form multifocal lenses with large areas of different refractive power without exhibiting sharp steps visible on a micro scale.

[0006] With reference to Figures 1a and 1b, the covering of a lens with a microlens with an anti-abrasion coating changes the refractive power of the microlens and therefore reduces or destroys the effect provided by the microlens. Indeed, the thickness of a microlens is usually about 1 μm to 2 μm, while the typical thickness of an anti-abrasion coating is about 3 μm. Thus, a surface with protruding elements such as a microlens is covered by an anti-abrasion coating (typically applied by immersion), the free surface of which is strictly different from the curvature of the lens it covers. Instead, the presence of the protruding elements causes a local deformation of the surface at said free surface.

[0007] As shown in FIG. 1b, a light ray incident on one such deformation undergoes a first refraction upon entering the anti-abrasion coating and a second refraction at the interface with the microlens of the base lens substrate, thus changing the path of the light ray compared to the path it would take in the absence of the anti-abrasion coating (FIG. 1a).

[0008] A solution has been proposed that consists in reducing this change in the microlens refractive power by reducing the thickness of the anti-abrasion coating. However, it is believed that the refractive index still changes, since the local refractive power P' of a microlens covered with this coating is approximately P-0.5 (P being the initial refractive power of the microlens without the coating). Furthermore, the protective properties against abrasion of the coating are greatly reduced, and therefore this solution is not satisfactory.

[0009] The same sort of thing or problem occurs with other optical structures present on the base lens substrate, for example structures such as Fresnel rings also experience perturbations in optical power when covered with an anti-abrasion coating. Summary of the Invention [Problem to be solved by the invention]

[0010] The object of the present invention is to provide a solution to the shortcomings of the prior art.

[0011] In particular, one object of the present invention is to provide an optical article comprising a base lens substrate, an anti-abrasion coating protecting said substrate, and at least one optical element (such as a microlens) or a plurality of optical elements, wherein the anti-abrasion coating does not reduce or inhibit the optical effect of the optical element and ensures good abrasion resistance due to its smooth surface, unlike the prior art where the anti-abrasion coating somewhat reproduces the surface microstructure. [Means for solving the problem]

[0012] The above mentioned objects are achieved by means of the feature combinations set out in the independent claims, while the dependent claims provide particular advantageous embodiments of the invention.

[0013] Optical articles and methods of making the same are disclosed.

[0014] Thus, in one embodiment, an optical article is disclosed, the optical article comprising: - a base lens substrate having first and second opposing lens surfaces; a protective layer having opposing first and second protective surfaces and a maximum thickness measured between the first and second protective surfaces in a direction perpendicular to the first protective surface, the first protective surface being disposed on the second lens surface; at least one or more optical elements, each of which defining a portion of one of the first protective surface and the second lens surface; at least one or more optical elements having a maximum height, measured in a direction perpendicular to a second lens surface carrying the optical element, that is 0.1 millimeters (mm) or less and a diameter that is 2.0 mm or less; Including, - The protective layer is composed of a cross-linked matrix and nanoparticles. - the refractive index n of said protective layer c is the refractive index of the optical element, n m lower, which results in a difference n m -n c is greater than 0.045, preferably greater than 0.10, or even greater than 0.15; and the maximum thickness of the protective layer is at least twice, preferably five times, the maximum height of the or each of the optical elements;

[0015] The protective layer serves to protect the base lens substrate from scratches and abrasion and is also conventionally referred to as an anti-abrasion coating or hard coating (HC).

[0016] In another embodiment, a method for making an optical article is disclosed, the method comprising: 1) providing a base lens substrate having opposing first and second lens surfaces, the base lens substrate comprising: providing at least one or more optical elements on the second lens surface, the optical elements having a maximum height, measured in a direction perpendicular to the second lens surface, that is 0.1 millimeters (mm) or less and a diameter that is 2.0 mm or less; 2) depositing, on a second lens surface of a base lens substrate comprising at least one or more optical elements, by a wet deposition technique, a curable composition suitable for forming a protective layer having opposed first and second protective surfaces; 3) curing the curable composition to form a protective layer; and 4) optionally repeating step 2 or step 2 and step 3; Including, the protective layer resulting from step 3 or 4 exhibits a second protective surface parallel to the second lens surface of the lens without the optical element; the protective layer encapsulates the or each optical element; the maximum thickness of the protective layer is at least twice, preferably at least five times, the maximum height of the or each optical element; The refractive index n of the protective layer c is the refractive index of the optical element, n m lower, which results in a difference n m -n c is greater than 0.045, preferably greater than 0.10, or even greater than 0.15.

[0017] The optical articles of the present disclosure include a protective layer that is thick enough to encapsulate each optical element (such as a microlens) and acts as an anti-abrasion coating.

[0018] The free surface of the protective layer (i.e. the second protective layer) is exactly the same as that of the surface of the base lens substrate (i.e. the second lens surface of the lens without optical elements) that it covers, and has the same base curve. In other words, the protective layer exhibits the same base curve as the second lens surface of the base lens substrate without optical elements. The protective layer comprises a smooth free surface (i.e. the smooth second protective layer). The second protective layer of the protective layer does not replicate the height variations present in the first protective surface. As a result, the shape of each optical element and its refractive power are not impaired by the coating, and therefore the adverse effects disclosed above in connection with the deposition of the coating do not occur. Furthermore, the protective layer exhibits good abrasion resistance due to its smooth surface plane, unlike the prior art, where anti-abrasion coatings somewhat reproduce the surface microstructure.

[0019] The smooth free surface of the protective layer is also particularly advantageous for the subsequent deposition of other functional coatings, such as anti-reflective, anti-soiling or anti-fog coatings, aesthetics and comfort.

[0020] In one embodiment of the present invention, the materials forming the protective layer and the optical element, respectively, are selected to have a refractive index difference of at least 0.1, the refractive index of the material of the protective layer being lower than the refractive index of the material forming the optical element, such that the refractive index difference allows for a desired optical power for the optical element to be obtained, and does not require the optical element to be so tall that it becomes aesthetically unsuitable, while having a physical height that is reasonable for the various techniques that one skilled in the art may use to create optical elements on a lens surface.

[0021] Unless otherwise specified, refractive indices in the present invention are expressed at 25° C. at a wavelength of 589 nm. Description of the drawings

[0022] For a more detailed understanding of the present disclosure and its advantages, reference is now made to the following brief description taken in conjunction with the accompanying drawings and detailed description, in which like reference numerals represent like elements. [Brief description of the drawings]

[0023] [Figure 1a-1b] It has already been explained and shows the effect of a protective layer covering a substrate with optical elements (microlenses) on the path of an incident light ray. [Figure 2a-2b] 1 shows a schematic diagram of an example of an optical article of the present invention. [Diagram 3] 2A-2C show schematic illustrations of spin-coating or spray-coating steps of a method for producing an optical article according to one embodiment; [Figure 4] 2 illustrates a schematic diagram of a Rodmeyer coating step of a method for producing an optical article according to one embodiment. [Diagram 5] This also relates to the Rodmeyer coating step of the method for producing an optical article according to one embodiment. [Figure 6] 2 illustrates a schematic of an inkjet coating step of a method for producing an optical article according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Optical article including optical element Optical articles according to the present invention will now be described.

[0025] The optical article is - a base lens substrate having first and second opposing lens surfaces; - a protective layer having opposing first and second protective surfaces, the first protective surface being disposed over the second lens surface; at least one or more optical elements each defining a portion of one of the first protective surface and the second lens surface.

[0026] Base Lens Material The base lens substrate 10 may comprise a single layer or may be formed of a laminate. The base lens substrate 10 preferably comprises at least a planar wafer 11, or a base lens 12 providing refractive power, or both, i.e. a base lens 12 providing refractive power and a wafer 11 supplementing the base lens 12 with an optical function as described below. In the example shown in Figure 2a, the base lens substrate 10 comprises a planar wafer 11 and a base lens 12. In the example shown in Figure 2b, the base lens substrate 10 comprises only a base lens 12.

[0027] The planar wafer 11 has no optical power and therefore does not provide correction to the wearer, but acts as a mechanical support for the other layers and optionally also provides one or more optical properties to the final optical article, such as at least one of the following optical functions: - amplitude filtering function, - Spectral filtering functions (edge-pass or band-pass filtering such as short-pass or long-pass or filtering of specific colors, e.g. by coloring or by incorporating photochromic or electrochromic functions, UV absorption, mirror, etc.), - Polarization function.

[0028] Planar wafer 11 refers to a film structure formed of a single film layer or a film stack structure formed of multiple film layers attached to each other. More precisely, planar wafer 11 may be formed of one or several ophthalmic grade functional films (e.g., having polarizing or photochromic properties), which optionally have an ophthalmic grade protective film on one or both sides of the ophthalmic functional film.

[0029] The planar wafer 11 may exhibit a thickness ranging from 20 μm to 700 μm, preferably from 30 μm to 600 μm. The protective layer, if present, may have a thickness of about 50 μm.

[0030] Transparent resin film or sheet materials suitable for forming planar wafers (including functional and protective films) include poly(vinyl alcohol) (PVA) or cellulose acylate-based materials, such as cellulose diacetate and cellulose triacetate (TAC). Other usable wafer materials can include polycarbonate, polysulfone, cellulose acetate butyrate (CAB), or cyclic oleophore copolymer (COC), polyacrylate, polyester, polystyrene, copolymers of acrylate and styrene, and poly(vinyl alcohol) (PVA). Polycarbonate-based materials include, for example, polybisphenol-A carbonate; homopolycarbonates, such as 1,1'-dihydroxydiphenyl-phenylmethylmethane, 1,1'-dihydroxydiphenyl-diphenylmethane, 1,1'-dihydroxy-3,3'-dimethyldiphenyl-2,2-propane, their mutual copolymer polycarbonates, and copolymer polycarbonates with bisphenol A.

[0031] The base lens 12 may be formed of an optical resin made of, for example, a thermoplastic or thermosetting plastic. In particular, the thermosetting material may be selected from, for example, polyamides, polyimides, polysulfones, polycarbonates and their copolymers, poly(ethylene terephthalate), and polymethyl methacrylate (PMMA).

[0032] The thermosetting material may be selected, for example, from cycloolefin copolymers such as ethylene / norbornene or ethylene / cyclopentadiene copolymers; homopolymers and copolymers of allyl carbonates of linear or branched aliphatic or aromatic polyols, such as homopolymers of diethylene glycol bis(allyl carbonate) (CR39®); homopolymers and copolymers of (meth)acrylic acid and its esters that may be derived from bisphenol A; polymers and copolymers of thio(meth)acrylic acid and its esters, polymers and copolymers of allyl esters that may be derived from bisphenol A or phthalic acid and aryl aromatics such as styrene, polymers and copolymers of urethanes and thiourethanes, polymers and copolymers of epoxies, and polymers and copolymers of sulfides, disulfides and episulfides, and combinations thereof. As used herein, (co)polymer is intended to mean copolymer or polymer. As used herein, (meth)acrylate is intended to mean acrylate or methacrylate.

[0033] Examples of substrates suitable for use in the present invention include those obtained from MR6®, MR7®, MR8®, MR174®, and MR10® resins (thermosetting polythiourethane resins). Various substrates based on polythiourethane resins are marketed by Mitsui Toatsu Chemicals Company, and these substrates and the monomers used in their preparation are described in particular in U.S. Pat. Nos. 4,689,387, 4,775,733, 5,059,673, 5,087,758, and 5,191,055.

[0034] The base lens substrate 10 or base lens 12 may advantageously be made from an optical resin, preferably a thermoplastic or thermosetting plastic, selected, for example, from polycarbonates of polyamides, polyimides, polysulfones, copolymers of poly(ethylene terephthalate); polyolefins, in particular polynorbornenes, homopolymers and copolymers of diethylene glycol bis(allyl carbonate), (meth)acrylic polymers and copolymers, in particular (meth)acrylic polymers and copolymers derived from bisphenol A, thio(meth)acrylic polymers and copolymers, polyurethane and polythiourethane homopolymers or copolymers, polycarbonates of epoxy polymers and copolymers; preferably made of polycarbonate, diethylene glycol bis(allyl carbonate) polymers, or episulfide polymers and copolymers made of a thermosetting polythiourethane resin having a refractive index of 1.60 or a thermosetting polythiourethane resin having a refractive index of 1.67, more preferably made of polycarbonate.

[0035] For example, it is possible to use polycarbonates such as Lexan OQ3820 (registered trademark) sold by Sabic, in particular having a refractive index of 1.586, diethylene glycol bis(allyl carbonates) such as CR39 (registered trademark) sold by PPG Industries, in particular having a refractive index of 1.5, or other polythiourethanes such as MR7 (registered trademark) sold by Mitsui Toatsu, in particular having a refractive index of 1.66.

[0036] The base lens 12 is preferably shaped to provide an appropriate optical power for correcting the wearer's refractive error, e.g., myopia or hyperopia. The base lens 12 can be a finished lens, a single vision lens, or a multifocal lens, such as a multifocal progressive lens.

[0037] In addition to the base lens 12 and / or the planar wafer 11, the base substrate 10 may include other layers, such as, for example, a photochromic trans-bonding® layer in front of the base lens 12 or may be deposited on the base lens or the planar wafer; - amplitude filtering function, - Spectral filtering functions (edge-pass or band-pass filtering such as short-pass or long-pass or filtering of specific colors, e.g. by coloring or by incorporating photochromic or electrochromic functions, UV absorption, mirror, etc.), - Polarization function The optical layer may include any additional layers incorporating optical functions such as

[0038] The base lens 12 may be a semi-finished lens, i.e. it may not provide a final refractive power, also called target power, of the lens produced from the semi-finished lens, but may provide a refractive power that is not a target power, said target power being obtained by subsequent surface processing of the semi-finished lens.

[0039] The base lens 12 may be an untrimmed lens, meaning that its peripheral shape is not adjusted to the shape of the frame in which it will be inserted. As shown in Figures 2a and 2b, the base lens substrate 10 comprises two opposing first and second lens surfaces, the two opposing main surfaces comprising a rear surface 101 and a front surface 102. In the example of Figure 2a, the front surface 102 of the base lens substrate 10 is formed by the front surface of the planar wafer 11, while in the example of Figure 2b, the front surface 102 of the base lens substrate 10 is formed by the front surface of the lens 12.

[0040] Optical element or elements The optical article 1 further comprises at least one optical element 30 or a plurality of optical elements having opposing first and second protective surfaces, e.g., defining a first protective surface disposed on a second lens surface protruding from one of the major faces of the base lens substrate 10. In a preferred embodiment, each optical element 30 protrudes from the front surface 102 of the base lens substrate 10.

[0041] By "protruding" it is meant that each optical element protrudes outwardly, i.e., away from, the surface of the base lens substrate 10. Thus, each optical element is convex.

[0042] In one embodiment, each optical element 30 may be formed of the same material as the base lens substrate 10 and may be integrally formed with the base lens substrate 10. If the base lens substrate 10 is a laminate, each optical element 30 may be formed of the same material as the layer from which it is protruded.

[0043] In one embodiment, each optical element 30 is formed of the same material as the base lens substrate 10, preferably selected from among thermoplastic or thermosetting plastics, such as polyamides, polyimides, polysulfones, polycarbonates of copolymers of poly(ethylene terephthalate); polyolefins, in particular polynorbornenes, homopolymers and copolymers of diethylene glycol bis(allyl carbonate), (meth)acrylic polymers and copolymers, in particular (meth)acrylic polymers and copolymers derived from bisphenol A, thio(meth)acrylic polymers and copolymers, polyurethane and polythiourethane homopolymers or copolymers, polycarbonates of epoxy polymers and copolymers; preferably made of polycarbonate, diethylene glycol bis(allyl carbonate) polymers, or episulfide polymers and copolymers made of a thermosetting polythiourethane resin having a refractive index of 1.60 or a thermosetting polythiourethane resin having a refractive index of 1.67, more preferably made of polycarbonate.

[0044] Hereinafter, optical elements are discrete optical elements on a microscopic scale that induce a local change in the optical power of an optical device.

[0045] In one embodiment, the optic is configured such that, along at least one cross-section of the lens, the mean sphere of the optic increases from a point on said cross-section towards the periphery of said cross-section.

[0046] According to one embodiment, the optical element is further configured such that, at least along one cross section of the lens, e.g. at least the same cross section as the cross section along which the mean sphere of the optical element increases, the mean cylinder increases from a point on said cross section, e.g. the same point as the mean sphere, towards the periphery of said cross section.

[0047] According to one embodiment, the optical element or optical elements are microlenses. The microlenses may be spherical, toric or have an aspheric shape. The microlenses may have a single focus, a cylindrical power or a non-focus. In a preferred embodiment, the microlenses can be used to arrest the progression of myopia or hyperopia. In that case, the base lens substrate comprises a base lens 12 that provides a refractive power that corrects myopia or hyperopia, and each microlens may provide a refractive power greater than that of the base lens 12 if the wearer has myopia, or may have a refractive power less than that of the base lens 12 if the wearer has hyperopia.

[0048] Within the meaning of this disclosure, a "microlens" has a contour shape that can be imprinted into a circle having a diameter of 0.8 mm or more and 3.0 mm or less.

[0049] For example, the microlenses may be evenly spaced along a circle centered at the optical center of the refractive region.

[0050] The mean cylinder power of the different microlenses can be adjusted based on the shape of the human retina.

[0051] The refractive zone may include a distance vision reference point, a near vision reference point, and a meridian joining the distance vision reference point and the near vision reference point. For example, the refractive zone may include a progressive addition lens adapted to fit a person's prescription or to slow the progression of hyperreflection in the eye of a person wearing the lens element.

[0052] The meridians correspond to the axial traces of the intersection of the main gaze direction and the surface of the lens.

[0053] Preferably, according to such an embodiment, the microlens is configured such that along any horizontal cross-section of the lens, under normal wear conditions, the mean sphere and / or mean cylinder of the microlens increases from the intersection of said horizontal cross-section with the meridian towards the periphery of the lens.

[0054] The mean sphere and / or mean cylinder growth function along a cross-section may vary depending on the position of said cross-section along a meridian.

[0055] In particular, the mean sphere and / or the mean cylinder growth function along the cross section is asymmetric, for example, the mean sphere and / or the mean cylinder growth function is asymmetric along the vertical and / or horizontal cross sections under standard wearing conditions.

[0056] At least one of the microlenses has an optical function that does not form an image on the retina of the human eye when the lens element is worn under normal wearing conditions.

[0057] Advantageously, such optical functionality of the microlenses in combination with a refractive region having at least one refractive power different from the prescription power can slow the progression of anomalous refraction in the eye of a person wearing the lens element.

[0058] The microlenses may be non-adjacent.

[0059] In the sense of this disclosure, two microlenses are not adjacent if, for all paths connecting the two microlenses, the refractive power based on the prescription of a human eye can be measured along at least a portion of each path.

[0060] Two microlenses are not adjacent if, when they lie on a sphere, it is possible to measure the curvature of said sphere for all paths connecting two optical elements along at least a portion of each path.

[0061] According to one embodiment, at least one of the microlenses has an optical function for focusing an image at a location other than the retina.

[0062] Preferably, at least 50%, such as at least 80%, such as all, of the microlenses have an optical function that focuses an image at a location other than the retina.

[0063] According to one embodiment, at least one of the microlenses has an aspheric optical function.

[0064] Preferably, at least 50%, such as at least 80%, such as all, of the microlenses have aspheric optical functions.

[0065] In the sense of this disclosure, an "aspheric optical function" should be understood as not having a single focal point.

[0066] At least one microlens having an aspheric optical function is transparent.

[0067] These microlenses can be added in defined arrays such as circles, squares, or hexagons, or randomly.

[0068] The microlenses can cover a particular zone of the lens element, as well as the center or any other area.

[0069] The optical element density, and therefore the amount of refractive power, can be tailored according to the zone of the base lens substrate. Typically, microlenses are located at the periphery of the base lens substrate to increase the effect of the optical elements on myopia control, for example to compensate for peripheral defocus due to the peripheral shape of the retina.

[0070] According to one embodiment, at least one, for example all, of the plurality of microlenses has a shape configured to form a focal line in front of the retina of the human eye, in other words, such microlenses are configured such that any cross-sectional planes in which the light bundles transmitted through said microlenses converge, if any, are located in front of the retina of the human eye, but not regularly in the plane or in any of those cross-sectional planes.

[0071] According to one embodiment, at least one, for example all, of the microlenses having aspheric optical functions are multifocal refractive microlenses.

[0072] Within the meaning of this disclosure, microlenses that are "multifocal refractive microlenses" include bifocal (having two focal powers), trifocal (having three focal powers), progressive addition lenses with continuously varying focal powers, e.g., aspheric progressive surface lenses.

[0073] According to one embodiment, at least one multifocal refractive microlens has a toric surface, which is a surface of revolution that can be formed by rotating a circle or an arc around an axis of rotation that does not pass through its center of curvature (eventually located at infinity).

[0074] A toric lens has two different radial profiles that are orthogonal to each other, thus producing two different focal powers.

[0075] The toric and spherical surface elements of a toric lens produce an astigmatic light beam as opposed to a single point focus.

[0076] According to one embodiment, at least one of the microlenses with aspheric optical function, e.g., all of the optical elements, is a toric refractive microlens, e.g., a toric refractive microlens with a sphere value of 0 diopters (δ) or more and +5 diopters (δ) or less and a cylinder value of 0.25 diopters (δ) or more.

[0077] In a specific embodiment, the toric refractive micro-lenses may be purely cylindrical, ie, the minimum meridian power is zero, while the maximum meridian power may be strictly positive, for example less than 5 diopters.

[0078] According to one embodiment, at least one, for example all, of the microlenses have an optical function having high order optical aberrations, for example the microlenses are composed of continuous surfaces defined by Zernike polynomials.

[0079] The optical elements of the present invention, typically microlenses, have a maximum height measured in a direction perpendicular to the second lens surface carrying the optical element that is 0.1 millimeters (mm) or less, preferably 2 to 20 micrometers (μm), and a diameter that is 2.0 mm or less, preferably 0.8 to 2.0 millimeters (mm).

[0080] 2a and 2b, it can be noticed that the surface of the base lens substrate exhibiting the microlenses 30, typically the front surface 102, is convex and formed by two types of outer surfaces: the first outer surface is the outer surface of each optical element having a local curvature variation due to the shape of the microlenses, while the second outer surface is the surface of the base lens substrate located between the microlenses, having less or no local curvature variation. Preferably, the difference induced by the local curvature variation of the microlenses compared to the surrounding second type of surfaces is at least 1D.

[0081] Thus, the base lens substrate exhibits a greater average thickness at the microlenses than away from the microlenses, with the maximum thickness of the substrate being reached at the maximum thickness point of the microlenses.

[0082] According to another embodiment, the at least one optical element or the optical elements are Fresnel structures, diffractive structures such as microlenses defining the respective Fresnel structures, permanent technological bumps or phase shifting elements. They can also be refractive optical elements such as microprisms and light dispersive optical elements such as small protrusions or cavities or any type of element that creates irregularities on the substrate.

[0083] protective layer The protective layer, which serves to protect the base lens substrate 10 from scratches and abrasion, completely encapsulates the optical elements. The maximum thickness of the protective layer, measured between the first and second protective surfaces in a direction perpendicular to the first protective surface, is at least two times, and preferably at least five times, the maximum height of each of the optical elements.

[0084] The maximum thickness of the protective layer in the present invention is measured in a direction perpendicular to the first protective surface between the first and second protective surfaces. Such thickness corresponds to the maximum thickness at any point on the surface. It does not correspond to the thickness above the optical elements, but to the total thickness (including the height of the optical elements), because the protective layer is also present between the optical elements.

[0085] Typically, the maximum thickness of the protective layer can be less than, equal to, or between any two of 200 micrometers (μm), 150 μm, 100 μm, 90 μm, 80 μm, 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, 10 μm, or less, while being at least 2 times, preferably 5 times, for example 2.5 to 12 times, or 2.5 to 8 times greater than the maximum height of the optical element or optical elements.

[0086] Furthermore, the minimum thickness of the protective layer is measured at the point of the maximum height of the optical element, more specifically the point of the maximum height of the optical element, at which point the minimum thickness of the protective layer measured from the point is equal to or less than the height of the optical element at that point or 10 μm, whichever is higher, and preferably equal to or less than 2 / 3 or even half of the height of the optical element, preferably equal to or less than 2 μm, for example 1 μm to 5 μm.

[0087] In certain embodiments, protective layer 20 covers the surface of base lens substrate 10 from which each optical element (typically a microlens) 30 protrudes, such that each optical element is completely encapsulated by protective layer 20. Protective layer 20 thus has a first protective surface 22 in contact with base lens substrate 10 and each optical element protruding therefrom, and a second protective surface 21 opposite the first protective surface.

[0088] In an embodiment, as shown in Figures 2a and 2b, the protective layer 30 covers the front or second lens surface 102 of the base lens substrate. Thus, in that case, the interface between the protective layer 20 and the base lens substrate 10 is formed by the rear or first protective surface 22 of the protective layer 20 and the front or second lens surface 102 of the base lens substrate.

[0089] In one embodiment, the surface of the protective layer at the interface with the base lens substrate is concave, whereas the second protective surface of the protective layer 21, which is the free surface of the protective layer 20, is convex and smooth and presents the same base curve as the surface of the base lens substrate 10, and in particular, due to the manufacturing method of the protective layer, as disclosed in more detail below, the second lens surface does not carry any optical elements.

[0090] Furthermore, the refractive indices of the materials forming the microlenses 30 and the materials forming the anti-abrasion coating 20 are different so as to cause the variations in local optical power provided by the microlenses to occur.

[0091] The refractive index n of the material forming the protective layer c is the refractive index n of the material from which the microlens is made m Lower.

[0092] More precisely, the refractive index n of the protective layer c is the refractive index of the optical element, n m lower, which results in a difference n m -n c is greater than 0.045, preferably greater than 0.10, or even greater than 0.15.

[0093] In the embodiment, the refractive index n of the material forming the protective layer c is the refractive index n m lower, which results in a difference n m -n cis greater than 0.09, preferably greater than 0.1, 0.3, or even greater than 0.5. In practice, for an optical element such as a microlens of a given diameter and a given desired optical power, the addition of an abrasion-resistant coating tends to increase the maximum height of the optical element required to achieve said optical power. On the other hand, the more significant the difference between the material forming the abrasion-resistant coating and the material forming the optical element, the lower said maximum height will be required and the easier the manufacture of the base lens substrate and its microlenses will be.

[0094] The protective layer may be any layer conventionally used as an abrasion-resistant coating in the field of ophthalmic lenses, provided that the curable composition for forming said protective layer can be deposited by wet deposition techniques onto the optical element to be coated.

[0095] The protective layer typically consists of a crosslinked matrix and nanoparticles, in other words, the protective layer consists of a nanocomposite material.

[0096] The crosslinked or cured matrices of the present invention may be made, for example, from acrylic compounds, epoxy compounds, epoxyacrylic compounds, silane compounds, epoxysilane compounds, polyurethaneacrylic compounds, siloxane compounds, and any mixtures of these compounds.

[0097] The protective coating of the present invention comprises particles, more precisely nanoparticles, selected to reduce its refractive index. Nanoparticles useful in the present invention exhibit a diameter of less than 70 nm, preferably less than 50 nm, more preferably less than 30 nm, are well dispersed in the matrix, and exhibit a surface that is chemically compatible with the crosslinked matrix, preferably exhibiting a chemical reaction between the surface of the nanoparticle and the compound used to form the matrix.

[0098] Nanoparticles useful in the present invention are typically silica nanoparticles (SiO 2), for example, hollow silica nanoparticles, functionalized or surface-modified silica nanoparticles, functionalized or surface-modified hollow nanoparticles, the refractive index of which is between 1.04 and 1.4, and mixtures thereof.

[0099] For example, to reduce the refractive index of a protective layer with an inherent refractive index of about 1.49, silica particles with a refractive index in the range of 1.4 to 1.5 (Nanocryl C-150 (50% silica dispersed in trimethylolpropane triacrylate - TMPTA)) can be used.

[0100] Surface-treated SiO dispersed in a solvent or monomer 2 Other non-limiting examples of commercially available products include Nanocryl® C-140 (50% hexanediol diacrylate in SiO2) from Evonik Industrie GmbH (Germany). 2 50%), Nanocryl® C-165 (alkoxylated pentaerythritol tetraacrylate 50% in SiO 2 50%) from Nissan Chemical America (Pasadena, TX, USA) and IPA-AC-2101 (Si0 dispersed in 70 wt.% isopropyl alcohol). 2 30 wt%) and PM-AC-2101 (Si0 dispersed in 70 wt% 1-methoxy-2-propanol) 2 30% by weight.

[0101] The refractive index of the hard coat can be further reduced by using hollow nanoparticles, such as hollow silica nanoparticles, which are known to have a refractive index of 1.04 to 1.4 depending on the manufacturing process: one example of a suitable hollow silica nanoparticle is Thrulya, a colloidal hollow silica nanoparticle manufactured by JGC C&C. Alternatively, silica and hollow silica nanoparticles can be used in combination. Thus, a hard coating can be obtained that is a protective layer with a refractive index of less than 1.5, preferably 1.4.

[0102] The anti-abrasion and / or anti-scratch hard coatings are preferably prepared from curable or crosslinking compositions comprising at least one alkoxysilane and / or one of its hydrolysates, for example obtained by hydrolysis with a hydrochloric acid solution. After the hydrolysis stage, which generally lasts from 2 to 24 hours, preferably from 2 to 6 hours, a catalyst can optionally be added. In order to improve the optical quality of the deposit, preferably surface-active compounds are also added.

[0103] Among the curable compound coatings recommended in the present invention, mention may be made of coating compositions based on epoxy silane hydrolysates, such as those described, for example, in EP 0 614 957, US 4 211 823 and US 5 015 523.

[0104] Curable coating compositions suitable for forming protective coatings may also be formed into crosslinked thermoset materials or composites.

[0105] Curable compositions of materials suitable for forming anti-wear coatings can be found in US Patent Publication No. 2007238804.

[0106] A preferred composition for the protective coating of the invention is that disclosed in the applicant's French patent FR 2 702 486. It comprises an epoxytrialkoxysilane, colloidal silica and a catalytic amount of an aluminium-based curing catalyst, for example aluminium acetylacetonate, the remainder essentially consisting of solvents conventionally used in the preparation of such compositions. Preferentially, the hydrolysates used are γ-glycidoxypropyltrimethoxysilane (GLYMO) and dimethyldiethoxysilane (DMDES) hydrolysates or γ-glycidoxypropyltrimethoxysilane (GLYMO) and triethylorthosilicate (TEOS) hydrolysates.

[0107] Other preferred compositions for forming the protective coating of the present invention include a multifunctional acrylate monomer, such as 1,6-hexanediol diacrylate and dipentaerythritol hexaacrylate or mixtures thereof, a silane compound such as a vinyl alkoxysilane, such as vinyltrimethoxysilane, a multifunctional epoxy compound, such as trimethylolpropane triglycidyl ether, silica nanoparticles, a free radical photoinitiator or one cationic photoinitiator or mixtures thereof, and a surfactant, such as a silicone hexaacrylate material and a fluorocarbon modified polysiloxane or mixtures thereof.

[0108] Another preferred composition for forming the protective coating of the present invention includes a multifunctional acrylate monomer, such as 1,6-hexanediol diacrylate, silica nanoparticles, such as hollow silica nanoparticles, such as surface-modified hollow silica nanoparticles, and a catalyst, such as a free radical photoinitiator.

[0109] Another material for forming the protective coating of the present invention having a refractive index of 1.49 (and therefore capable of providing a refractive index gap of greater than 0.1 when the base lens substrate 10 is made of polycarbonate) may be the composition of Example 3 of EP 0 614 957, which is incorporated herein by reference and which states in said patent: "80 parts of 0.1 N hydrochloric acid were added dropwise to a solution containing 224 parts GLYMO and 120 parts DMDES. The hydrolyzed solution was stirred at room temperature for 24 hours after which 718 parts of 30% colloidal silica in methanol, 15 parts aluminum acetylacetonate, and 44 parts ethyl cellosolve were added. A small amount of surfactant was added. The theoretical dry content (TDC) of the composition was approximately 13% of the solid material from the hydrolyzed DMDES." GLYMO is defined in said patent as glycidoxypropyltrimethoxysilane. DMDES is defined in said patent as dimethyldiethoxysilane. The resulting total dry matter content was approximately 35% of the composition.

[0110] The refractive index difference between the protective layer 20 and the optical element 30 may induce reflections at the interface between the protective layer and the surface carrying the optical element. In that case, the optical article 1 preferably comprises a quarter-wave layer 40 between the base lens substrate 10 and the optical element 30, suitable for reducing the amount of reflection. For example, the refractive index RI=(n c .n m ) 1 / 2 A quarter wave layer (also written λ / 4 layer) having the following formula can be used.

[0111] Detailed examples of λ / 4 layers are disclosed in commonly owned US Pat. No. 7,008,690.

[0112] 2b, optical article 1 may include one or more coatings on each of its front and rear surfaces. For example, the front surface, i.e., the second surface of the protective layer, may be coated with at least one additional coating, including one or more of the following: an anti-reflective coating, a photochromic coating, an anti-soiling coating, an anti-fog coating, a tinted coating, a self-healing coating, a water-repellent coating, an anti-static coating, an anti-UV coating, or a blue light blocking coating.

[0113] Method for manufacturing optical article With reference to Figures 3 to 6, methods of forming the optical articles described above will now be disclosed.

[0114] The present invention also relates to a method for producing an optical article, in particular the optical article disclosed hereinabove.

[0115] The method for producing an optical article comprises the steps of: 1) providing a base lens substrate having opposed first and second lens surfaces, the base lens substrate including at least one optical element or a plurality of optical elements on the second lens surface having a maximum height, measured in a direction perpendicular to the second lens surface, of 0.1 millimeters (mm) or less and a diameter of 2.0 mm or less; 2) depositing, on a second lens surface of the base lens substrate, the second lens surface including at least one or more optical elements, by a wet deposition technique, a curable composition suitable for forming a protective layer having opposed first and second protective surfaces; 3) curing the curable composition to form a protective layer; and 4) optionally repeating step 2 or step 2 and step 3; Including, the protective layer resulting from step 3 or 4 exhibits a second protective surface parallel to the second lens surface of the lens without the optical element; the protective layer encapsulates the or each optical element; the maximum thickness of the protective layer is at least 2 times, preferably at least 5 times, for example 2.5 to 12 times or 2.5 to 8 times, the maximum height of the at least one optical element or each of the optical elements; The refractive index n of the protective layer c is the refractive index of the optical element, n m lower, which results in a difference n m -n c is greater than 0.045, preferably greater than 0.10, or even greater than 0.15.

[0116] Curable compositions suitable for forming protective layers useful in the present method The curable composition suitable for forming the protective layer useful in the present method is any one of those described above in relation to the optical article.More generally, all the properties described above in relation to the optical article also apply to said article or to the method for producing said optical article, said method being another object of the present invention.Conversely, all the properties described below in relation to the method also apply to the optical article.

[0117] Therefore, a curable composition suitable for forming the protective layer comprises at least: nanoparticles, preferably silica nanoparticles, and a compound selected from the group consisting of epoxyalkylalkoxysilanes, multifunctional acrylate monomers, multifunctional epoxy compounds, multifunctional acrylate monomers, urethane monomers, silane compounds, and any mixtures of these compounds; - a catalyst, such as a free radical photoinitiator or one cationic photoinitiator, or a mixture thereof; and - optionally surfactants and / or solvents Includes.

[0118] The epoxyalkylalkoxysilanes useful in the present invention are preferably selected from glycidyl(C1-3 alkyl)-(C1-3 alkyl)-di(1-3 alkoxy)silane and glycidyl(C1-3 alkyl)-tri(C1-3 alkoxy)silane. Hydrolysis of the C1-3 alkoxy groups releases volatile alcohols (methanol, ethanol, propanol), which are easily evaporated from the curable coating composition. The (epoxy)(alkoxy)silanes are advantageously 3-glycidoxypropyl-methyldiethoxysilane and / or 3-glycidoxypropyl-trimethoxysilane.

[0119] The multifunctional acrylate monomer useful in the present invention may be selected from the group consisting of diacrylate, triacrylate, tetraacrylate, and hexaacrylate monomers, such as pentaerythritol triacrylate or pentaerythritol tetraacrylate. In particular, the multifunctional monomer is preferably selected from the group consisting of 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, dipropylene glycol diacrylate pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, silicone hexaacrylate, and mixtures thereof. The addition of the multifunctional acrylate monomer may improve adhesion, stainability, scratch resistance, and adhesion to thermoplastic substrates.

[0120] Polyfunctional epoxy compounds useful in the present invention include diglycerol tetraglycidyl ether, dipentaerythritol tetraglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, e.g. pentaerythritol polyglycidyl ether, trimethylolethane triglycidyl ether, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, triphenylolmethane triglycidyl ether, triphenol triglycidyl ether, tetraphenylolethane glycidyl ether, tetraglycidyl ether of tetraphenylol ether, p-aminophenol triglycidyl ether, 1,2,6-hexanetriol triglycidyl ether, The polyepoxide may be selected from the group consisting of glycerol triglycidyl ether, diglycerol triglycidyl ether, glycerol ethoxylate triglycidyl ether, castor oil triglycidyl ether, propoxylated glycerin triglycidyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol glycidyl ether, neopentyl glycol diglycidyl ether, cyclohexane dimethanol diglycidyl ether, dipropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, dibromoneopentyl glycol diglycidyl ether, hydrogenated diphenol A diglycidyl ether, (3,4-epoxycyclohexane)methyl 3,4-epoxycyclohexane carboxylate, and mixtures thereof. The addition of such polyepoxides improves the toughness and adhesion of the resulting cured coating to the thermoset substrate.

[0121] When a multifunctional acrylate monomer is used together with an epoxyalkoxysilane, the coating composition may further comprise at least one free radical photoinitiator, preferably from 1% to 15% by weight, more preferably from 1.5 to 10% by weight, of the free radical photoinitiator with respect to the multifunctional acrylate monomer. Such free radical photoinitiators are, for example, haloalkylated aromatic ketones such as chromomethylbenzophenone, some benzoin ethers such as ethyl benzoin ether and isopropyl benzoin ether, dialkoxyacetophenones such as diethoxyacetophenone and α,α-dimethoxy-a-phenylacetophenone, hydroxyketones such as (1-[4-(2-hydroxyethoxy)-phenyl]2-hydroxy-2-methyl-1-propan-1-one) (CIBA Irgacure® 2959), 1-hydroxy-cyclohexyl-phenyl ketone (CIBA Irgacure® 184), and 2-hydroxy-2-methyl-1-phenylpropan-1-one (e.g. Darocur® sold by CIBA), alpha aminoketones, especially those containing a benzoyl moiety, also known as alpha aminoacetophenones, e.g. 2-methyl-1-[4-phenyl]-2-morpholinopropan-1-one (CIBA Irgacure® 907), (2-benzyl-2-dimethylamino-1-5(4-morpholinophenyl)-butan-1-one (CIBA Irgacure® 369), monoacyl and bisacyl phosphine oxides and sulfides, such as phenylbis(2,4,6-trimethylbenzoyl)-phosphine oxide (Irgacur® 819 sold by CIBA), triacyl phosphine oxides, liquid photoinitiator blends (e.g., GENOCURE LTM sold by Rahn USA), and mixtures thereof. Similarly, the multifunctional epoxy monomers may be used with at least one cationic photoinitiator, which may be selected from triallylsulfonium salts, diaryliodonium salts, or combinations thereof, preferably triallylsulfonium salts.The triallylsulfonium salt or the diallylodonium salt used in the present invention advantageously has a counterion with low nucleophilicity, and is preferably selected from triallylsulfonium hexafluoroantimonate, triallylsulfonium hexafluorophosphate, diallylodonium hexafluoroantimonate, and diallylodonium hexafluorophosphate. Triallylsulfonium hexafluoroantimonate is available, for example, from Dow Chemical Company under the trade name CYRACURE® UVI-6976 (50% by weight in propylene carbonate). Triallylsulfonium hexafluorophosphate is available, for example, from Dow Chemical Company under the trade name CYRACURE® UVI-6992 (50% by weight in propylene carbonate). Diallylodonium hexafluorophosphate is available, for example, from Ciba Specialty Chemicals Co., Ltd. under the reference number IRG-250, or from Aldrich under the reference number 548014. Diallylodonium hexafluoroantimonate is for example available from Sartomer Company under the reference SarCat CD 1012. The curable composition according to the invention may preferably comprise at least 1% by weight, preferably from 1% to 15% by weight, more preferably from 1.5% to 10% by weight of cationic photoinitiator, with respect to the total dry matter of the composition. Cationic and / or free radical photoinitiators are typically added to the alkoxysilane / acrylate composition.

[0122] The alkoxysilanes useful in the present invention are preferably selected from the group consisting of dialkyl-dialkoxysilanes, alkyl-trialkoxysilanes, alkenyl-trialkoxysilanes, and mixtures thereof. In a particular embodiment, the vinylalkoxysilane is vinyltrimethoxysilane. Silanes that do not have an epoxy group can be used as substitutes for the epoxyalkoxysilanes, but only as partial substitutes. The weight ratio of the epoxyalkoxysilane to the non-epoxy silane (particularly to the non-epoxyalkoxysilane) is defined as the silane ratio.

[0123] The curable coating composition includes nanoparticles, silica nanoparticles. 2 The inclusion of makes it possible to improve the scratch and abrasion resistance of the coating composition and of the resulting protective layer, and also to control, in particular to lower, its refractive index.

[0124] As mentioned above with respect to the optical article, the nanoparticles used to form a curable composition suitable for forming a protective layer are typically functionalized (or surface modified) silica nanoparticles or silica nanoparticles dispersed in a solvent or mixtures thereof, e.g. hollow silica nanoparticles having a refractive index of 1.04 to 1.4, hollow silica functionalized with a silicone binder such as 3-trimethoxysilylpropyl acrylate, or silica nanoparticles dispersed in trimethylolpropane triacrylate.

[0125] Colloidal silica particles may be added to the coating composition in an amount of up to 50% by weight, preferably 5-30% by weight, based on the total dry matter of the composition. An exemplary colloidal silica is 50% SiO in trimethylolpropane triacrylate (TMPTA) (Nanocryl® C-150). 2 Includes.

[0126] The curable compositions disclosed herein advantageously further comprise a small amount, preferably 0.05 to 1.5% by weight, of at least one surfactant. The surfactant is important for good wetting of the surface, so that the final hard coating has a pleasing appearance. The surfactant may comprise, for example, a poly(alkylene glycol)-modified polydimethylsiloxane or polyheptamethylsiloxane, or a fluorocarbon-modified polysiloxane. The curable compositions preferably comprise 0.1% to 0.3% of a fluorocarbon-modified polysiloxane, such as the commercially available product EFKA® 3034 sold by Ciba Specialty Chemicals, Inc., or the commercially available product FC-4434 sold by 3M, or EBECRYL® 1360, which is a silicone hexaacrylate material.

[0127] In some cases, for example when the coating composition contains many colloidal or nanoparticles, it may be necessary to use an organic solvent to control viscosity or improve flow properties. The amount of organic solvent is preferably not more than 30% by weight of the coating composition. The solvent is, for example, selected from alcohols, glycol ethers, polyols, and combinations thereof.

[0128] In certain embodiments, the method does not include a hydrolysis step prior to the UV curing step. In some embodiments, a cationic and / or free radical photoinitiator is added.

[0129] For example, a curable composition suitable for forming a protective layer may include a multifunctional acrylate monomer, such as 1,6-hexanediol diacrylate and dipentaerythritol hexaacrylate, or a mixture thereof, a silane compound, such as a vinylalkoxysilane, such as vinyltrimethoxysilane, a multifunctional epoxy compound, such as trimethylolpropane triglycidyl ether, silica nanoparticles, a free radical photoinitiator or a cationic photoinitiator, or a mixture thereof, and a surfactant, such as a silicone hexaacrylate material and a fluorocarbon modified polysiloxane, or a mixture thereof. This composition is of particular interest when both the base lens substrate and the optical lens are made of polycarbonate.

[0130] Another example of a curable composition suitable for forming the protective layer is a composition comprising a multifunctional acrylate monomer, such as 1,6-hexanediol diacrylate, silica nanoparticles, such as hollow silica nanoparticles, such as surface-modified hollow silica nanoparticles, and a catalyst, such as a free radical photoinitiator. This composition is also of particular interest when both the base lens substrate and the optical element are made of polycarbonate.

[0131] Depositing a curable coating using wet deposition techniques In the method of the present invention, a curable composition suitable for forming a protective layer is applied onto at least one or more optical elements to be coated by a wet deposition technique.

[0132] In particular, the curable composition is applied by a spin coating, spray coating, rod coating or inkjet coating step, preferably by an inkjet coating step, in such a way that the final cured coating, the protective layer, presents a smooth surface parallel to the surface of the base lens substrate without any optical elements or microstructures, and the second of the protective layers does not replicate height variations present in the first protective surface.

[0133] When a spin-coating step is used, a large amount of coating is deposited over the entire surface of the lens and the lens is rotated to trim the thickness to a target value.

[0134] When using spin-coating or spray-coating steps, the coating may present an uneven surface, either due to the tendency to replicate the structured surface of the substrate (in the case of spin-coating, curtain-coating, etc.) or due to the deposition technique itself (in the case of spray-coating) (Figure 3). In such an embodiment, in order to ensure obtaining a protective layer with a smooth surface (smooth second protective surface), a subsequent heating step at low temperature of the applied curable coating can be carried out after the thick layer of the composition has been deposited (i.e. between steps 3 and 4 for the purposes of the method of the invention). Such a low-temperature heating step at a temperature below the boiling point of the main solvent / monomer can reduce the viscosity of the curable composition.

[0135] Alternatively, to ensure obtaining a protective layer having a smooth surface, a leveling agent can be added to the curable composition to even out the surface tension of the wet coating composition.

[0136] The curable coating can be applied using a Mayer rod (or wire wound rod) coating technique. A large amount of coating is deposited on the lens, where a Mayer rod (constructed with a flexible core) is wound across the surface of the lens. Depending on the solids, the rod number is #6 to #15 to obtain a hard coat thickness of greater than 5 μm, more preferably greater than 10 μm (FIG. 5).

[0137] The advantage of the Mayer rod (or wire wound rod) coating technique is that it fills the spaces between the optical elements or microlenses and applies the coating thickness on the surface S1. The surface S1 is parallel to the uniform surface (i.e. the second lens surface) of the lens S0 (without optical elements) defined by the highest point of the optical element at a distance h1 from S0. The distance h1 represents the height of the optical element. The distance h3 is the maximum distance between the wires wound on the Mayer rod that is filled by the liquid curable coating. The distance h3 is defined by the geometry of the Mayer rod and, in the case of a wire wound rod, by the diameter of the wire wound around the rod. The thickness h2 is defined by h3 after leveling. The final thickness of the coating depends on h2 and the solids (as shown in FIG. 4). In this embodiment, the rod used to apply the coating has an axis parallel or nearly parallel to the surface S1. For very flat bases (e.g. semi-finished lenses used for high myopia prescriptions), a rigid, typically metal, rod can be used. However, preferably the rod is flexible enough to follow the curvature defined by S1.

[0138] The curable composition can also be applied using inkjet coating techniques. In such an embodiment, the deposition of the curable coating is performed in a pattern that is the complementary pattern of the height microstructures. Typically, the wet deposition steps include the following, as shown in FIG. 6: - a first step or a first pass of depositing a limited or measured amount of a curable coating composition only on the bottom of the optical element (only partial coverage of the microstructures) to obtain a first layer, - a second step or a second pass of depositing another limited amount of a curable coating composition on the first layer to provide a larger coverage and complete coverage of the optical element, followed by - An additional pass, or several additional passes, until a reasonable thickness is reached, typically until the maximum thickness or height of the curable coating composition measured in a direction perpendicular to the second base lens substrate is greater than two times, and preferably greater than five times, the maximum height of the optical element.

[0139] It should be noted that in this embodiment, the step of wet depositing comprises varying the amount of curable composition suitable for forming a protective layer depending on the local presence or absence of at least one optical element, such control being possible through a computer-implemented method such as that disclosed in EP19306294.0.

[0140] Optical Elements All the characteristics mentioned below in relation to the optical article, in particular the production of the microstructured lens substrate, also apply to the method.

[0141] According to a first embodiment, the base lens substrate and the at least one or a plurality of optical elements are formed in a single step, preferably by injection molding or casting. In a second embodiment, the plurality of optical elements can be produced by a surface processing step of the second lens surface or a depositing material step on the second lens surface, preferably by molding or inkjetting. The first embodiment is preferred.

[0142] In an embodiment, the method for producing an optical article may further include additional steps such as depositing at least one additional coating on the abrasion resistant coating and possibly on the major surface of the base lens substrate 10 without the optical elements (microlenses), said additional coating including an anti-reflective coating, a photochromic coating, an anti-soiling coating, an anti-fog coating, a tinted coating, a self-repelling coating, a water repellent coating, an anti-static coating, an anti-UV coating, or a blue light cut coating. The major surface of the base lens substrate without the microlenses may also be coated with an abrasion resistant coating.

[0143] If the base lens substrate 10 is or includes a semi-finished lens, the method may further include a finishing step including surfacing the semi-finished lens to obtain the desired target optical power and / or trimming the resulting lens. EXAMPLES

[0144] Example 1: The lens with the microlenses is made of polycarbonate (PC) Lexan OQ3820® sold by Sabic, whose refractive index is 1.586.

[0145] The hardcoat has a refractive index of 1.47 and is a nanocomposite photocurable hardcoat containing acrylic monomers and silica nanoparticles.

[0146] Curable coating composition: In a UV-opaque bottle, vinyltrimethoxysilane (32.1 g) is added to trimethylolpropane triglycidyl ether (20.1 g), 1,6-hexanediol diacrylate (8.3 g), and dipentaerythritol hexaacrylate (20.8 g).

[0147] The mixture is stirred until homogenous. Then UVI-6976 (triacrylsulfonium hexafluoroantimonate, 0.8 g), UVI-6992 (triacrylsulfonium hexafluorophosphate, 0.3 g), Darocur 1173 (2-hydroxy-2-methylpropiophenone, 1.6 g) and Irgacure 819 (phenylbis2,4,6-trimethylbenoyl)phosphine oxide, 0.4 g) are added along with surfactants EBECRYL 1360 (0.8 g) and FC4434 (0.6 g). The mixture is stirred again until homogenous. Nanocryl C-150 (50% nanosilica dispersed in trimethylolpropane triacrylate-TMPTA, 10.3 g) is added last and the coating is left to mix overnight before filtering.

[0148] After the curable coating composition is deposited on the microstructured lens by one of the processes described in the previous embodiments, the curable coating composition is heated at 50°C for 10 minutes (if smoothing is required) and then UV cured under an H+ bulb for 5 to 10 seconds (depending on thickness).

[0149] The refractive index of the resulting coating after UV curing is about 1.47 (at 633 nm).

[0150] Example 2: The lens with the microlenses is made of polycarbonate (PC) Lexan OQ3820® sold by Sabic, whose refractive index is 1.586.

[0151] The hard coat has a refractive index of about 1.40 and is a photocurable hard coat comprising acrylic monomers and hollow silica nanoparticles such as Thrulya (colloidal hollow silica nanoparticles manufactured by JGC C&C).

[0152] Curable coating composition: To disperse high concentrations of hollow silica nanoparticles in UV-curable monomers, the inorganic nanoparticles were surface modified using a coupling agent, 3-triethoxysilylpropyl acrylate.

[0153] Hollow silica nanoparticles (sold by JGC) with an average particle size of 45 nm were dispersed in water. A silane coupling agent was added to the dispersion, and the mixture was heated under reflux for 4 hours. The surface-modified nanoparticles were then dispersed in 1-ethoxy-2-propanol (by centrifugation).

[0154] Surface modified hollow silica nanoparticles dispersed in 1-methoxy-2-propanol were mixed with the UV-curable monomer 1,6-hexanediol diacrylate. The photoinitiator Irgacure® 907 was added at 5% wt (monomers making up 95% wt).

[0155] After the curable coating composition is deposited on the microstructured lens by one of the processes described in the previous embodiments, the curable coating composition is heated at 80° C. for 2 minutes and then UV cured for 10 to 30 seconds (depending on thickness).

[0156] The modified hollow silica nanoparticles make up 60% wt of the final coating, which has a refractive index (at 633 nm) of 1.38.

[0157] Example 3: The formulation is similar to that of Example 2, except that the surface-modified hollow silica nanoparticles make up 40% wt of the final coating. The refractive index (at 633 nm) is 1.43. Some of the embodiments of the present disclosure are described in [Item 1] to [Item 18] below. [Item 1] An optical article, - a base lens substrate having first and second opposing lens surfaces; a protective layer having opposing first and second protective surfaces and a maximum thickness measured in a direction perpendicular to the first protective surface between the first and second protective surfaces, the first protective surface being disposed over the second lens surface; At least one or more optical elements, each comprising: defining a portion of one of the first protective surface and the second lens surface; At least one or more optical elements having a maximum height, measured in a direction perpendicular to the second lens surface carrying the optical element, that is 0.1 millimeters (mm) or less and a diameter that is 2.0 mm or less; Including, the protective layer is composed of a crosslinked matrix and nanoparticles; The refractive index n of the protective layer c is the refractive index n of the at least one or each optical element m lower, which results in a difference n m -n c is greater than 0.045, preferably greater than 0.10, or even greater than 0.15; and 13. An optical article, wherein said maximum thickness of said protective layer is at least twice, preferably at least five times, the maximum height of the or each optical element. [Item 2] 2. The optical article according to item 1, wherein the or each optical element is selected from the group consisting of microlenses, Fresnel structures, diffractive structures such as microlenses defining each Fresnel structure, permanent technological bumps, and phase-shifting elements, preferably microlenses. [Item 3] 3. The optical article of any one of items 1 or 2, wherein the or each optical element has a maximum height, measured in a direction orthogonal to the second lens surface, between 2 and 20 micrometers (μm) and a diameter between 0.8 and 2.0 millimeters (mm). [Item 4] 4. The optical article according to any one of items 1 to 3, wherein the crosslinked matrix is ​​made of an acrylic compound, an epoxy compound, an epoxy acrylic compound, a silane compound, an epoxy silane compound, a polyurethane acrylic compound, a siloxane compound, and any mixture of the above-mentioned compounds. [Item 5] 5. The optical article according to any one of items 1 to 4, wherein the nanoparticles are selected from silica nanoparticles having a refractive index in the range of 1.04 to 1.5, for example hollow silica nanoparticles having a refractive index in the range of 1.04 to 1.4, functionalized or surface-modified silica nanoparticles, functionalized or surface-modified hollow nanoparticles, and mixtures thereof. [Item 6] 6. The optical article according to any one of items 1 to 5, wherein the base lens substrate and the optical element are both made of a thermoplastic or thermosetting plastic selected from, for example, polycarbonates of polyamides, polyimides, polysulfones, copolymers of poly(ethylene terephthalate); polyolefins, in particular polynorbornenes, homopolymers and copolymers of diethylene glycol bis(allyl carbonate), (meth)acrylic polymers and copolymers, in particular (meth)acrylic polymers and copolymers derived from bisphenol A, thio(meth)acrylic polymers and copolymers, polyurethane and polythiourethane homopolymers or copolymers, polycarbonates of epoxy polymers and copolymers; preferably polycarbonates, diethylene glycol bis(allyl carbonate) polymers, or episulfide polymers and copolymers made with a thermosetting polythiourethane resin having a refractive index of 1.60 or with a thermosetting polythiourethane resin having a refractive index of 1.67. [Item 7] 7. The optical article according to any one of items 1 to 6, wherein the base lens substrate is a semi-finished lens. [Item 8] 8. The optical article according to any one of the preceding claims, wherein the second surface of the protective layer is covered with at least one additional coating comprising one or more of the following: an anti-reflective coating, a photochromic coating, an anti-soiling coating, an anti-fog coating, a tinted coating, a self-repelling coating, a water-repellent coating, an anti-static coating, an anti-UV coating, or a blue light cut coating. [Item 9] A method for producing an optical article, comprising the steps of: 1) providing a base lens substrate having opposing first and second lens surfaces, the base lens substrate comprising at least one or more optical elements on the second lens surface having a maximum height, measured in a direction perpendicular to the second lens surface, that is 0.1 millimeters (mm) or less and a diameter that is 2.0 mm or less; 2) depositing, on the second lens surface of the base lens substrate comprising the at least one or the plurality of optical elements, by a wet deposition technique, a curable composition suitable for forming a protective layer having opposed first and second protective surfaces; 3) curing the curable composition to form the protective layer; and 4) optionally repeating step 2 or step 2 and step 3; Including, the protective layer resulting from step 3 or 4 exhibits a second protective surface parallel to the second lens surface of the lens without optical elements; the protective layer encapsulates the or each optical element; the maximum thickness of said protective layer is at least twice, preferably at least five times, the maximum height of the or each optical element; The refractive index n of the protective layer c is the refractive index n of the at least one or each optical element m lower, which results in a difference n m -n c is greater than 0.045, preferably greater than 0.10, or even greater than 0.15. [Item 10] 10. The method according to item 9, wherein the wet deposition step is a spin-coating step, a spray-coating step, a rod-coating step or an inkjet coating step, preferably an inkjet coating step. [Item 11] The wet deposition step is an inkjet coating step, the steps comprising: - a first step or a first pass of depositing a limited or measured amount of said curable coating composition only on the bottom of said at least one or said plurality of optical elements (only partially covering the microstructures) to obtain a first layer, - a second step or a second pass of depositing another limited amount of said curable coating composition on said first layer to provide a larger coverage of said at least one or each optical element, thereafter an additional pass, or several additional passes, until the maximum thickness or height of the curable coating composition, measured in a direction perpendicular to the second base lens substrate, is greater than two times, and preferably greater than five times, the maximum height of the or each optical element. 11. The method according to item 9 or 10, comprising: [Item 12] said curable composition suitable for forming a protective layer comprises at least nanoparticles, preferably silica nanoparticles; a compound selected from an acrylic monomer, an epoxy monomer, an epoxy acrylic compound, a silane compound, an epoxy silane compound, a polyurethane acrylic compound, a siloxane compound, and a mixture of any of the aforementioned compounds; a catalyst, such as a free radical photoinitiator or one cationic photoinitiator, or a mixture thereof; - optionally surfactants and / or solvents The method according to any one of items 9 to 11, comprising: [Item 13] 13. The method according to any one of items 9 to 12, wherein the nanoparticles used to form the curable composition suitable for forming the protective layer are functionalized (or surface modified) silica nanoparticles or silica nanoparticles dispersed in a solvent or a mixture thereof, such as hollow silica nanoparticles having a refractive index in the range of 1.04 to 1.4, hollow silica functionalized with a silicone binder such as 3-trimethoxysilylpropyl acrylate or silica nanoparticles dispersed in trimethylolpropane triacrylate. [Item 14] 14. The method according to any one of items 9 to 13, wherein the curable composition suitable for forming a protective layer comprises a multifunctional acrylate monomer, such as 1,6-hexanediol diacrylate and dipentaerythritol hexaacrylate or a mixture thereof, a silane compound, such as a vinylalkoxysilane such as vinyltrimethoxysilane, a multifunctional epoxy compound, such as trimethylolpropane triglycidyl ether, silica nanoparticles, a free radical photoinitiator or a cationic photoinitiator, or a mixture thereof, and a surface active agent, such as a silicone hexaacrylate material and a fluorocarbon modified polysiloxane, or a mixture thereof. [Item 15] 15. The method according to any one of items 9 to 14, wherein the curable composition suitable for forming a protective layer comprises a multifunctional acrylate monomer, such as 1,6-hexanediol diacrylate, silica nanoparticles, such as hollow silica nanoparticles, such as surface-modified hollow silica nanoparticles, and a catalyst, such as a free radical photoinitiator. [Item 16] 17. The method according to any one of claims 9 to 16, wherein the base lens substrate and the at least one or more optical elements are formed in a single step, preferably by injection molding or casting. [Item 17] 17. The method according to any one of items 9 to 16, further comprising depositing at least one additional coating on the protective layer, the additional coating comprising an anti-reflective coating, a photochromic coating, an anti-soiling coating, an anti-fog coating, a colored coating, a self-repelling coating, a water-repellent coating, an anti-static coating, an anti-UV coating, or a blue light cut coating. [Item 18] 18. The method according to any one of items 9 to 17, wherein the base lens substrate is a semi-finished lens, the method further comprising surface finishing and / or trimming the lens.

Claims

1. An optical article, a base lens substrate having first and second opposing lens surfaces; a protective layer having opposing first and second protective surfaces and a maximum thickness measured in a direction perpendicular to the first protective surface between the first and second protective surfaces, the first protective surface being disposed over the second lens surface; At least one optical element, each comprising: defining a portion of one of the first protective surface and the second lens surface; at least one optical element having a maximum height, measured in a direction perpendicular to the second lens surface carrying the optical element, that is 0.1 millimeters (mm) or less and a diameter that is 2.0 mm or less; Including, the protective layer is composed of a crosslinked matrix and nanoparticles; The refractive index n of the protective layer ｃ is the refractive index n of the at least one optical element ｍ lower, so the difference n ｍ -n ｃ is greater than 0.3, and 13. An optical article, wherein the maximum thickness of the protective layer is at least twice the maximum height of the at least one optical element.

2. 2. The optical article of claim 1, wherein the at least one optical element is selected from the group consisting of a microlens, a Fresnel structure, a diffractive structure, a permanent technological bump, and a phase shifting element.

3. 2. The optical article of claim 1, wherein the at least one optical element has a maximum height, measured in a direction perpendicular to the second lens surface, that is between 2 and 20 micrometers (μm) and a diameter that is between 0.8 and 2.0 millimeters (mm).

4. 2. The optical article of claim 1, wherein the crosslinked matrix is ​​made of an acrylic compound, an epoxy compound, an epoxy acrylic compound, a silane compound, an epoxy silane compound, a polyurethane acrylic compound, a siloxane compound, and a mixture of any of the above compounds.

5. 2. The optical article of claim 1, wherein the nanoparticles are selected from silica nanoparticles having a refractive index in the range of 1.04 to 1.5, functionalized or surface-modified silica nanoparticles, functionalized or surface-modified hollow nanoparticles, and mixtures thereof.

6. 2. The optical article of claim 1, wherein the base lens substrate and the optical element are both made of a thermoplastic or thermoset plastic selected from polycarbonates of polyamides, polyimides, polysulfones, copolymers of poly(ethylene terephthalate); polyolefins, homopolymers and copolymers of diethylene glycol bis(allyl carbonate), (meth)acrylic polymers and copolymers, thio(meth)acrylic polymers and copolymers, polyurethane and polythiourethane homopolymers or copolymers, epoxy polymers and copolymers; episulfide polymers and copolymers.

7. The optical article of claim 1 , wherein the base lens substrate is a semi-finished lens.

8. A method for producing an optical article, comprising the steps of: 1) providing a base lens substrate having opposing first and second lens surfaces, the base lens substrate comprising at least one optical element on the second lens surface having a maximum height, measured in a direction perpendicular to the second lens surface, that is 0.1 millimeters (mm) or less and a diameter that is 2.0 mm or less; 2) depositing, on the second lens surface of the base lens substrate including the at least one optical element, by a wet deposition technique, a curable composition suitable for forming a protective layer having opposing first and second protective surfaces; 3) curing the curable composition to form the protective layer; and 4) optionally repeating step 2 or steps 2 and 3; Including, the protective layer resulting from step 3 or 4 exhibits a second protective surface parallel to the second lens surface of the lens without optical elements; the protective layer encapsulates the at least one optical element; a maximum thickness of the protective layer is at least twice the maximum height of the at least one optical element; The refractive index n of the protective layer ｃ is the refractive index n of the at least one optical element ｍ lower, so the difference n ｍ -n ｃ is greater than 0.3, method.

9. The method of claim 8 , wherein the wet deposition step is a spin-coating step, a spray-coating step, a rod-coating step, or an inkjet-coating step.

10. The wet deposition step is an inkjet coating step, the steps comprising: a first step or a first pass of depositing a limited or measured amount of said curable composition only on the bottom of said at least one optical element (only partially covering the microstructures) to obtain a first layer; a second step or a second pass of depositing another limited amount of said curable composition on said first layer to obtain a larger coverage of said at least one optical element, then an additional pass, or several additional passes, until the maximum thickness or height of the curable composition measured in a direction perpendicular to the second lens surface is greater than twice the maximum height of the at least one optical element. The method of claim 8 , comprising:

11. said curable composition suitable for forming a protective layer comprises at least Nanoparticles, a compound selected from acrylic monomers, epoxy monomers, epoxyacrylic compounds, silane compounds, epoxysilane compounds, polyurethaneacrylic compounds, siloxane compounds, and mixtures of any of the aforementioned compounds; A catalyst, - optionally surfactants and / or solvents The method of claim 8 , comprising:

12. 12. The method of claim 11 , wherein the nanoparticles used to form the curable composition suitable for forming the protective layer are functionalized (or surface-modified) silica nanoparticles or silica nanoparticles dispersed in a solvent or a mixture thereof.

13. 9. The method of claim 8, wherein the curable composition suitable for forming a protective layer comprises a multifunctional acrylate monomer, a silane compound, a multifunctional epoxy compound, silica nanoparticles, a free radical photoinitiator or a cationic photoinitiator, or a mixture thereof, and a surfactant.

14. The method of claim 8 , wherein the curable composition suitable for forming a protective layer comprises a multifunctional acrylate monomer, silica nanoparticles, and a catalyst.

15. The method of claim 8 , wherein the base lens substrate and the at least one optical element are formed in a single step.

Images