Patent ID: 7884040

Claim:
Optical glass comprising, on a final oxide basis and mass percentage basis: 23.0 to 30.0% of SiO 2 , 24.0 to 40.0% of TiO 2 , 16.88 to 30.0% of Nb 2 O 5 and 10.5 to 23.0% of Na 2 O, wherein amounts of TiO 2 , Nb 2 O 5 , Na 2 O and K 2 O satisfy the relationship: (TiO 2 +Nb 2 O 5 )/(Na 2 O+K 2 O)=3.0 to 3.85, and TiO 2 /Nb 2 O 5 ≦2.0 the optical glass contains no lead component, and the optical glass has a refractive index of at least 1.83 and an Abbe number of at most 26.