Optical flint sheen with temperature independent path length in the range n depth e = 1,59 - 1,65 and v low e = 55 - 46 on the basis of barium - niobium - phosphate glasses

摘要

An optical glass with a path length independent of temperature comprises between 40 and 55% by weight P2O5, between 40 and 54% by weight BaO and between 6 and 12% by weight Nb2O5. Part of the BaO may be replaced by SrO or CaO. Minor amounts of SiO2 or B2O3 may be included as may other metal oxides such as ZnO, Sb2O3 and La2O3.