Optisches Element mit einer Spiegel-Oberflächenbeschichtung und Verfahren zur Herstellung dieser Beschichtung

The invention relates to an optical element comprising a transparent substrate provided with a superficial mirror coating having improved characteristics of adhesion to the substrate and of resistance to abrasion, and to a method for forming the coating. The superficial mirror coating includes a plurality of superimposed layers, namely: an adhesion layer including a first material adapted to firmly adhere to the substrate; a reflection layer including a second material having a high refraction index selected from the group comprising: CrxOy, TiO2, ZnSe, ZnS and mixtures thereof, wherein x is a number comprised between 1 and 2 and y is a number comprised between 1 and 3; a coloring and optionally abrasion-resistance layer, including a third material having a refraction index lower than the refraction index of the second material.