Patent ID: 8207074

Claim:
An optical glass comprising, in terms of mass % on an oxide basis: P 2 O 5 : from 10 to 18%; Bi 2 O 3 : from 37 to 64%; Nb 2 O 5 : from 5 to 25%; Na 2 O: from more than 4.1 to 10%; GeO 2 : from 0 to 5.0%; K 2 O: from 0 to 2%; Li 2 O: from 0 to 0.2%; WO 3 : from 0 to less than 20%; TiO 2 : from 0 to 3%; and B 2 O 3 : from 0 to 2%, wherein the optical glass has a refractive index n d of 1.98 or more and an Abbe's number ν d of 20 or less.