Low density alkali free optical glass - based on borosilicate contg. lime, titania, and lead oxide having high refractive index and low dispersion

摘要

Alkali face optical borosilicate glass with refractive gridex nd of 1.68-1.72, Abbe no Vd of 38-46 and density =3.2 g/cm3 comprises by wt. 20-30% SiO2, 10-25% B2O3, 15-45% CaO, 3-15% TiO2, 1-10% PbO, 0-3% MgO, 0-10% Al2O3, 0-10% ZrO2, 0-3% Z-O, 0-10% BaO, 0-5% La2O3. Glass contains no rare and expensive raw materials and only a relatively small amt. of TiO2, hence it is inexpensive. It has a good resistance to crystallisation and weathering. The compsn. can be produced continuously.