LAYER WITH A POROUS LAYER AREA, AN INTERFERENCE FILTER CONTAINING SUCH A LAYER AND A METHOD FOR THE PRODUCTION THEREOF

摘要

The invention relates to a layer with an area made of a porous material extending from the surface of the layer to the inside of the latter, wherein the dimension of the porous layer area in the direction perpendicular to the surface of the layer exhibits different values. The invention also relates to a method for producing a layer with a porous area or a layer system, wherein said porous layer area is formed by etching and means are used to choose a physical dimension in correlation with the etching speed of the etching process in order to form at least one etching gradient.