Patent ID: 8247336

Claim:
An optical glass composition comprising, in % by mole, 0-25.0% of SiO 2 , 20.0-40.0% of B 2 O 3 , 3.0-15.0% of ZnO, 0-10.0% ZrO 2 , 2.0-7.0% of Ta 2 O 5 , 6.0-25.0% of La 2 O 3 , 5.0-22.0% of Gd 2 O 3 , 66.5% or less of La 2 O 3 +Gd 2 O 3 +B 2 O 3 and 26.0% or more of La 2 O 3 +Gd 2 O 3 , wherein the composition contains no Li 2 O, and wherein the composition has a refractive index (nd) to the d-line of 1.83-1.86, an Abbe number (vd) to the d-line of 43-46, and a liquidus temperature of 1300° C. or lower.