Patent ID: 8203169

Claim:
Glass comprising, as represented by mol % based on oxides, from 27 to 30% of P 2 O 5 , from 52 to 63% of SnO, ZnO of at most 1/7 of the content of SnO, from 0.5 to 5% of CaO, from 0 to 5% of B 2 O 3 , from 0 to 3% of Ga 2 O 3 , from 0 to 3% of In 2 O 3 and from 0 to 3% of La 2 O 3 , wherein the total of P 2 O 5 +SnO is from 85 to 92% and the glass contains substantially no Li 2 O, Na 2 O and K 2 O.