Patent ID: 7897533

Claim:
An optical glass composition comprising, in % by mole, 14.0% or more and 31.0% or less of SiO 2 , 19.0% or more and 40.0% or less of B 2 O 3 , 0% or more and 5.0% or less of Li 2 O, 0% or more and 12.0% or less of ZnO, 0% or more and 12.0% or less of ZrO 2 , 15.0% or more and 26.0% or less of La 2 O 3 , 24.0% or more and 38.0% or less of La 2 O 3 +ZrO 2 , 2.0% or more and 5.0% or less of Ta 2 O 5 and 4.0% or more and 16.0% or less of Gd 2 O 3 , and having a refractive index (nd) to the d-line of 1.83 or higher and 1.87 or lower and an Abbe number (νd) to the d-line of 43 or higher and 47 or lower.