Glasses of low density and high index of refraction for ophthalmic and optical applications

摘要

This invention relates to glasses especially suitable for optical and ophthalmic applications which exhibit densities less than about 2.65 g/cm3, refractive indices between about 1.595-1.607, and Abbe numbers between about 40-47, and which consist essentially, in weight percent on the oxide basis, of -SiO2 45-55 MgO and/or BaO and/or -B2O3 5-13 SrO and/or La2O3 0-6 -Al2O3 0-5 CaO 0-12 -Li2O 1-7.5 ZnO 0-8 -Na2O 1-9 ZrO2 0-7 -K2O >10-24 TiO2 9.5-17.5 - As2O3 and/or Sb2O3 0-1 -and 13.5 < TiO2 + ZrO2 + La2O3 + MgO + <23.5 -CaO + BaO + ZnO + SrO -