Patent ID: 8399371

Claim:
An optical glass comprising in % by weight: 10% or more and 17% or less of SiO 2 ; 23% or more and 30% or less of B 2 O 3 ; 0.1% or more and 1% or less of Al 2 O 3 ; 2% or more and 3.5% or less of Li 2 O; 1% or more and 4% or less of BaO; 10% or more and 20% or less of CaO; 0.5% or more and 6% or less of ZnO; 22% or more and 30% or less of La 2 O 3 ; 0.5% or more and 7% or less of Gd 2 O 3 ; and 5% or more and 11% or less of Y 2 O 3 , wherein the optical glass satisfies the following conditional expressions (1) and (2), 0.35< A/B< 0.70 (1) 0.80< C/D< 1.0 (2) wherein A is the content in % by the weight of SiO 2 , B is the content in % by the weight of B 2 O 3 , C is the content in % by the weight in total of La 2 O 3 , Gd 2 O 3 and Y 2 O 3 and D is the content in % by the weight in total of SiO 2 and B 2 O 3 .