OPTICAL GLASS WITH OPTICAL POSITION N LOW D = 1.63 PLUS / MINUS (1.5X10 HIGH-2), V LOW D = 59.5 PLUS / MINUS 1.0, WITH HIGH CHEMICAL RESISTANCE AND LOW CRYSTALLIZATION TILT

摘要

An optical glass having nD=1.63+/-(1.5x10-2), vD=59.5+/-1.0, a high chemical stability and a low tendency to crystallization is provided, consisting essentially of (in percent. by weight): -SiO2 23-27 -B2O3 24-30 -SrO 18-31 -La2O3 10-16 -Al2O3 2-4 -BaO 0-10 -CaO 0-5 -ZnO 0-6 -Y2O3 0-5 -ZrO2 0-2 -Li2O, Na2O and/or K2O 0-1.5 -As2O3 and/or Sb2O3 0-1 -F and/or Cl 0-1, - wherein the sum of SiO2+B2O3 is 50-53, the weight ratio SiO2:B2O3 is 0.8-1.0, the sum SrO+BaO is 26-31, and the sum ZnO+La2O3 is 12-17.