Optical glass containing neither cdo or tho2, having a refractive index of 1,73 1,78 and has a coefficient of abbe of 30 to 34, and having a very good stability for the divitrification

摘要

The invention relates to a new optical glass without cdo or tho, whose refractive index is between 1,73 and abbe 1,78 and the coefficient of between 30 and 34, and which has a stability for the vitrification particularly good. / p & & p & this glass has the following composition (by weight): sio 12 - 20, bo 10 - 18, pbo 50 - 60, alo 2 - 7, zno 0 - 4, zro 0,5 - 3, lao 2 - 10, soc 0 - 5%, mo 0 - 1, (mo nao, k, l) tio 0 - 5, the ratio siobo being between 1,0 and 1,5.