Optical glass with refractive indexes of 1.60-1.69 and Abbe numbers of at least 54 with particularly low density and particularly good chemical stability

摘要

Optical glass compositions having refractive indexes of 1.60-1.69 and Abbe numbers higher than 54 as well as with a density of less than 3.4 g/cm3, and which are distinguished in that they have good chemical stability, comprising (in percent by weight): 5-30 percent SiO2; 20-55 percent B2O3; 13-40 percent CaO; 3-25 percent La2O3; and optionally one or more of the following: up to 7 percent ZrO2, up to 2 percent TiO2, up to 9 percent Al2O3, up to 11 percent MgO, up to 10 percent ZnO, up to 10 percent SrO, and up to 12 percent BaO.