Patent ID: 7396787

Claim:
A lead-free optical glass having a refractive index n d of from 1.50 to 1.57, an Abbé number ν d of from 61 to 70 and a composition, in percent by weight, based on oxide content of: P 2 O 5 40-60 Al 2 O 3 1-20 B 2 O 3 0-<5 Na 2 O 1-25 K 2 O 0-30 Li 2 O 0-<1 ΣM 2 O >15-40 BaO 1-20 ZnO 2-14 SrO 0-5 CaO 0-5 MgO 0-5 ΣMO 5-25, wherein the optical glass is free of coloring components.