LENS WITH SURFACE MICROSTRUCTURES ENCAPSULATED BY A THICK LOW REFRACTIVE INDEX HARD COAT

The invention relates to an optical article comprising a base lens substrate having a at least one or a plurality of optical elements such as microlenses, a Fresnel structures, etc protruding from a surface thereof, and a hard coat covering encapsulating each optical elements. More particular it relates to an optical article comprising: a base lens substrate having opposing first and second 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 disposed on the second lens surface; and at least one or a plurality of optical elements, each: defining a portion of one of the first protective surface and the second lens surface; having a maximum height, measured in a direction perpendicular to the second lens surface carrying them, that is less than or equal to 0.1 millimeters (mm) and a diameter that is less than or equal to 2.0 mm. wherein the protective layer is composed of a crosslinked matrix and nanoparticles and the index nc of said protective layer is lower than the index nm of the at least one or each optical element such that the difference nm - nc is greater than 0.045, preferably greater than 0.10, or even greater than 0.15; and wherein the maximum thickness of the protective layer is at least 2 times, preferably at least 5 times of the maximum height of the at least one or each of the optical elements. The invention also relates to the method for forming such optical articles, typically comprising an inkjet step. L'invention concerne un article optique comprenant un substrat de lentille de base ayant au moins un élément optique ou une pluralité d'éléments optiques tels que des microlentilles, des structures de Fresnel, etc faisant saillie à partir d'une surface de celles-ci, et une couverture de revêtement dur encapsulant chaque élément optique. Plus particulièrement, l'invention concerne un article optique comprenant : un substrat de lentille de base ayant des première et seconde surfaces de lentille opposées ; une couche de protection ayant des première et seconde surfaces de protection opposées et une épaisseur maximale, mesurée dans une direction perpendiculaire à la première surface de protection entre les première et seconde surfaces de protection, la première surface de protection étant disposée sur la seconde surface de lentille ; et au m