| 摘要 |
<p>A new optical glass is proposed which has a refractive index of >/=1.69, an Abbe number >/=38 and a density of less than or equal to 3.25 g/cm<3> and which represents a further development of the optical glass disclosed in British Patent application No. 2083016A, being distinguished from the said glass in that, for the purpose of improved aptitude for continuous tank-furnace production and increased resistance to acids, it contains in % by weight:- SiO2 18-36; B2O3 3-18; GeO2 0-8; Al2O3 0-6; LiO2 0-12; Na2O 0-14; K2O 0-18; MgO 0-10.5; CaO 7-17.5; P2O5 0.5-4; SrO 0-13; BaO 0-17; ZnO 0-15; PbO 0-10; TiO2 3-14; Nb2O5 0-13; WO3 0-10; ZrO2 0-15; La2O3 0-20; Y2O3 0-16; GdO3 0-16; Yb2O3 0-16; Ta2O5 0-13; HfO2 0-5; SnO2 0-6; wherein SiO2 + B2O3 + Al2O3 + P2O3 = 38.5-41.5; Li2O + Na2O + K2O = 2-18; MgO + CaO = 13-17.5; and TiO2 + Nb2O5 + WO3 = 10-21.</p> |
