Patent ID: 8178595

Claim:
A BaO- and/or PbO-free X-ray opaque glass having a refractive index n d of about 1.480 to about 1.517 and an aluminum equivalent thickness of at least about 180%, comprising in % by weight based on oxide SiO 2 63-70 B 2 O 3 12-16 Al 2 O 3 0-4 Li 2 O 0-1 Na 2 O 0-3 K 2 O 2-7 Cs 2 O 6-13 ZrO 2 0-4 La 2 O 3 >2-7 Σ alkali metal oxides 11-18 Cs 2 O + La 2 O 3 >8.