Optical glasses having extended refractive index gradients

摘要

The invention relates to optical glasses which have an extended refractive index gradient ( DELTA nmax > 0.05; DELTA x10% >/= 150 mu m) and are used as base material for inhomogeneous optical media. The object of the invention is to produce hydrolysis-stabilised glasses which contain an extended refractive index gradient through K/Tl ion exchange. The object is achieved according to the invention in that the glasses are composed of from 12.1 to 25.0 mol% of K2O from 66.0 to 81.7 mol% of SiO2 and in addition contain from 0 to 17.0 mol% of B2O3 and/or from 0 to 4.4 mol% of ZnO and/or from 0 to 1.0 mol% of Al2O3 and/or from 0 to 2.1 mol% of PbO and/or from 0 to 0.5 mol% of KF, and have been provided with a refractive index gradient through K/Tl ion exchange.