Patent ID: 8207075

Claim:
An optical glass, comprising: B 2 O 3 , La 2 O 3 , TiO 2 , Nb 2 O 5 and Ta 2 O 5 , wherein the optical glass further comprises, in terms of % by mass, SiO 2 0 to 6%, Li 2 O less than 0.5%, WO 3 1% or more, and B 2 O 3 8.81 to 22%, wherein the ratio, as % by mass, of TiO 2 /Nb 2 O 5 is at most 0.26 and GeO 2 /Nb 2 O 5 is at most 0.38, and wherein the optical glass has optical constants, a refractive index (n d ) of more than 1.9, an Abbe number (ν d ) of less than 33 and a partial dispersion ratio (θ g, F) of at most 0.615.