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EP-3807440-B1 - OPTICAL ARTICLE HAVING DIRECTIONAL MICRO- OR NANOSTRUCTURED THIN FILM COATING, AND ITS PROCESS

EP3807440B1EP 3807440 B1EP3807440 B1EP 3807440B1EP-3807440-B1

Inventors

  • TROTTIER-LAPOINTE, William
  • FAURE, BRUCE
  • BALOUKAS, BILL
  • VERNHES, RICHARD
  • ZABEIDA, OLEG
  • MARTINU, LUDVIK
  • WOODWARD, Sasha
  • DESJARDINS-LECAVALIER, Nicolas
  • GAGNON, Julien

Dates

Publication Date
20260506
Application Date
20190613

Claims (13)

  1. An ophthalmic lens comprising a substrate with a front main face and with a rear main face, at least one of the main faces being coated with a columnar micro- or nano-structured coating, wherein - the substrate and the ophthalmic lens are transparent or can be put in a state where they are transparent in at least a part of the visible region ranging from 380 to 780 nm, along at least one incidence angle; - said columnar micro- or nano-structured coating comprises at least an array of columns comprising each a core and an upper layer covering said core, the core and the upper layer being structurally and/or chemically different and wherein said core and/or upper layer have light absorbing properties or can be put in a state where they have light absorbing properties with an extinction coefficient " k " equal to or higher than 10 -2 in at least a part of the light spectrum ranging from 250 to 2500 nm and are able to cause a change in transmission or in reflection of incident light through the ophthalmic lens as a function of the angle of incidence of light, wherein the core of the columns has a porosity that is equal to or higher than 30 %, preferably equal to or higher than 45 %, especially ranging from 75 to 85 %, and wherein the upper layer is absent from the columns head, so that the parts of the columns core that are situated less than a predefined distance from the substrate main face are covered with the upper layer, when the parts of the columns core that are situated at the predefined distance or more than the predefined distance of the substrate main face are not covered by the upper layer.
  2. The ophthalmic lens according to claim 1, wherein the columns have a height ranging from 50 to 1000 nm, preferably ranging from 200 to 300 nm.
  3. The ophthalmic lens according to any one of the preceding claims, wherein a tilt angle beta β ranging from 0 to 50° is defined between the columns and the at least one main face of the substrate.
  4. The ophthalmic lens according to any one of the preceding claims, wherein the at least one main face of the substrate contains predetermined patterns covered with a columnar micro- or nano-structured coating.
  5. The ophthalmic lens according to any one of the preceding claims, wherein the core and/or the upper layer have permanent light absorbing properties with an extension coefficient " k " equal to or higher than 10 -2 at least in a part of the visible range from 380 to 780 nm.
  6. The ophthalmic lens according to claim 5, wherein the core and/or the upper layer comprise(s) one or more substoichiometric oxides, such as the substoichiometric oxides of ZrO 2 , TiO 2 , SiO, SiO 2 , Fe 2 O 3 , Al 2 O 3 and/or Ta 2 O 5 and/or substoichiometric nitrides, such as the substoichiometric nitrides of Si 3 N 4 or substoichiometric fluorides, such as the substoichiometric fluorides of MgF 2 .
  7. The ophthalmic lens according to claim 5, wherein the core and/or the upper layer further has (have) conducting properties and comprise(s) one or more materials selected from: diamond like carbon DLC, graphene/graphite; metals, such as Au, Al, Ag, Cu, Ti, Cr; conductive nitrides like TiN, ZrN, TaN; semiconductors, doped or not, such as Si, Ge, GaAs; or transparent conductive oxides such as ITO, SnO 2 , AZO.
  8. The ophthalmic lens according to any one of claims 1 to 4, wherein the core and/or the upper layer can be put in a state where they have light absorbing properties with an extension coefficient " k " equal to or higher than 10 -2 at least in a part of the visible range ranging from 380 to 780 nm and are configured to reversibly switch from a deactivated state to an activated state upon the application of activation or deactivation means, respectively.
  9. The ophthalmic lens according to claim 8, wherein the core and/or the upper layer comprise(s) one or more chromogenic materials, such as WO 3 , VO 2 , or oxygen-containing yttrium hydride.
  10. The ophthalmic lens according to any one of the preceding claims 1 to 9, wherein the core is transparent and the upper layer has light absorbing properties or can be put in a state where it has light absorbing properties with an extension coefficient " k " equal to or higher than 10 -2 in at least a part of the light spectrum ranging from 250 to 2500 nm.
  11. The ophthalmic lens according to claims 1 to 5 and 7 to 10, wherein the core comprises one or more stoichiometric oxides such as SiO 2 , WO 3 , TiO2, ZrO 2 , Al 2 O 3 Ta 2 O 5 , or nitrides such as Si 3 N 4 , or fluorides, such as MgF 2 or a mixture of organic-inorganic materials, such as a metal oxide with an organosilicon compound.
  12. The ophthalmic lens according to any one of claims 1 to 9, wherein the core and/or the upper layer has (have) a high refractive index that is higher than or equal to 1.8, preferably higher than or equal to 1.9, and especially higher than or equal to 2 or has (have) a medium refractive index that is lower than 1.8, preferably lower than or equal to 1.7 and especially lower than or equal to 1.6.
  13. Method of manufacture of an ophthalmic lens comprising a substrate with a front main face and with a rear main face, at least one of the main faces being coated with a columnar micro- or nano-structured coating, wherein - the substrate and the ophthalmic lens are transparent or can be put in a state where they are transparent in at least a part of the visible region ranging from 380 to 780 nm, along at least one incidence angle; - said columnar micro- or nano-structured coating comprises at least an array of contiguous columns comprising each a core and an upper layer covering said core, the core and the upper layer being structurally and/or chemically different and wherein said core and/or upper layer have light absorbing properties or can be put in a state where they have light absorbing properties with an extinction coefficient " k " equal to or higher than 10 -2 in at least a part of the light spectrum ranging from 250 to 2500 nm; the method comprising the following steps: (a) depositing on the at least one main surface of the substrate, the core by physical directional deposition, preferably by glancing angle deposition, to create the array of contiguous columns; (b) depositing, on the core of the columns, at least one - upper layer by atomic layer deposition; (c) removal of at least part of the upper layer, the parameters of the deposition of the core and of the upper layer being controlled so as to provide a change in transmission or reflection of incident light through the ophthalmic lens as a function of the angle of incidence of light, wherein the core of the columns has a porosity that is equal to or higher than.30%, preferably equal to or higher than 45%, especially ranging from 75% to 85%.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention The present invention relates to an ophthalmic lens comprising on one of its main faces, such as its rear face and/or its front face, a specific columnar micro- or nano-structured coating which absorbs light based on the direction of the incoming light. The ophthalmic lens may be used especially as a spectacle lenses. The present invention also relates to a method of manufacturing an ophthalmic lens comprising on one of its main faces such columnar micro- or nano-structured coating. 2. Description of related art It is known to coat ophthalmic lenses or screens, whether mineral or organic, with interference coatings. These interference coatings are generally formed of a multilayer stack of dielectric mineral materials such as SiO, SiO2, Si3N4, TiO2, ZrO2, Al2O3, MgF2 or Ta2O5. Traditional antireflective coatings are designed and optimized to reduce reflection on the lens surface in the visible region, typically within the spectrum range of 380 to 780 nm. They are also designed, especially in the case of an ophthalmic lens, to prevent the formation of annoying reflections to the wearer and his interlocutors. A reflective coating achieves the opposite effect, that is, it increases the reflection of light rays. Such a type of coating is used, for example, to obtain a mirror effect in solar lenses. However, light directionality is not easily managed with these kinds of traditional interference coatings. Indeed, for a standard antireflective coating or a mirror coating, the residual reflected color changes as a function of the incident angle as the electromagnetic spectrum moves towards lower wavelengths. This phenomenon is called the blue shift. However, the total transmitted light does not change substantially and once again cannot easily be managed with such traditional coatings. Therefore, creating an interferential thin film coating that has a neutral residual color, while being able to decrease transmission (or to increase absorption) as a function of the angle of incidence is not easy, or even impossible as these parameters (incidence angle, residual reflected light and transmission) cannot be fully optimized independently. Different kinds of solutions have been proposed in the prior art to manage the light absorption or the light transmission as function of the incident light. For instance, document US 8 503 122 describes a film stack having a light control film and a color shifting film proximate to one another. Especially, the light control film is configured to regulate the directionality of transmitted light. The document describes hence the addition of a filter to reduce the visibility of a display, such as a computer screen, based on the angle of incidence. It is also known from the prior art that polarized films reduce light from reflections and/or absorption. However, an ophthalmic lens comprising such a polarized film generally has a maximum light transmission of 50 % by default, which might be too limiting, for example for night driving where lens transmission must be higher than 80%. A relevant prior art document is known as WO 2015/013631. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an ophthalmic lens that is able to selectively absorb the light as a function of the angle of incidence in at least a part of the light spectrum ranging, especially from 250 to 2500 nm, such as 250 to 1400 nm. Especially, an object of the present invention is to provide an ophthalmic lens that is able to modulate the light transmission or the light absorption according to the directionality of the light, while having at the same time an aesthetically pleasing appearance. For that purpose, the present invention relates to an ophthalmic lens such as defined in the set of claims, comprising a substrate with a front main face and with a rear main face, at least one of the main faces being coated with a columnar micro- or nano-structured coating, wherein the substrate and the ophthalmic lens are transparent or can be put in a state where they are transparent in at least a part of the visible region ranging from 380 to 780 nm, along at least one incidence angle;said columnar micro- or nano-structured coating comprises at least an array of columns comprising each a core and an upper layer covering said core, the core and the upper layer being structurally and/or chemically different and wherein said core and/or upper layer have light absorbing properties or can be put in a state where they have light absorbing properties with an extinction coefficient "k" equal to or higher than 10-2 in at least a part of the light spectrum ranging from 250 to 2500 nm and are able to cause a change in transmission or in reflection of incident light through the optical article as a function of the angle of incidence of light, wherein the core of the columns has a porosity that is equal to or higher than 30 %, preferably equal to or higher than