Patent ID: 7524782

Claim:
An optical glass comprising (in wt.-%): SiO 2 : 35-75 Al 2 O 3 : 17-35 B 2 O 3 : 0-5 P 2 O 5 : 1-17 SnO 2 + ZrO 2 + TiO 2 : 0.1-8 Na 2 O + K 2 O + Cs 2 O + Li 2 O: 0.1-8 CaO + MgO + SrO + BaO + ZnO: 0.1-8 refining agents: ≦1.0 and further comprising a maximum of 500 ppm of any impurity selected from the group formed by coloring agents, noble metals and halogenides; further comprising a maximum of 120 ppm of Fe 2 O 3 ; and having a coefficient of thermal expansion in the range between 0° C. and 50° C. being 4.1·10 −6 /K at the most.