Patent ID: 7323427

Claim:
A boron aluminosilicate glass comprising at least the following components (in wt.-%): SiO 2 40 to 47 B 2 O 3 0.1 to 6 Al 2 O 3 0.1 to 4 P 2 O 5 0.1 to 4 Li 2 O 0 to 2 Na 2 O 2 to 7 K 2 O >6.5 to 11 MgO 0 to 5 CaO 0. to 6 BaO 6 to 14 ZnO 20 to 25 La 2 O 3 0 to 1.5 ZrO 2 1 to 7. wherein said glass is free of lead, and wherein said glass is an optical glass.