OPTICAL GLASS

摘要

The invention relates to optical glasses that are composed as follows: 5 - 35 % by weight of SiO2, 55 - 88 % by weight of PbO; 0 - 10 % by weight of B2O3; 0 - 5 % by weight of Na2O, 0 - 5 % by weight of K2O; 0 - 10 % by weight of TiO2, 0 - 10 % by weight of ZrO2; 0 - 10 % by weight of La2O3; 0 - 10 % by weight of BaO; 0 - 10 % by weight of ZnO, with the proviso that S (Na2O; K2O): 0 = x = 8 and S (TiO2; ZrO2; La2O3; ZnO; BaO): x = 15. The glasses are particularly suitable for LCD projection purposes, especially rLCD projectors. The inventive glasses are glasses from the heavy flint-glass and lanthane heavy flint glass type and have a stress-optical coefficient approaching zero while having a good chemical resistance and sufficient Knoop hardness and are characterized by excellent melting and workability properties. They are therefore suitable for use in fields of application that benefit from low stress-optical effects.