A cesium-containing optical glass comprising, by weight, 32-56% of SiO.sub.2, 6-25% of K.sub.2 O, 6-32% of Cs.sub.2 O, 0-30% of BaO, 0-2.5% of MgO, 5-34% of ZnO, 0-3% of ZrO.sub.2 and 0-5% of SnO.sub.2, provided that the total proportion of BaO, MgO and ZnO is 8-40% and the total proportion of ZrO.sub.2...http://www.google.fr/patents/US4472030?utm_source=gb-gplus-shareBrevet US4472030 - Cesium-containing optical glass
