Patent ID: 7833920

Claim:
An optical glass which consists of, in terms of % by mass on the basis of oxides, 37-45% of SiO 2 , 12-20% of B 2 O 3 , 2-7% of Li 2 O, 0.1-10% of ZnO, 2-15% of Al 2 O 3 , 25-30.7% of BaO, 0-5% of K 2 O, 0-10% of Na 2 O, 0-20% of Gd 2 O 3 , optionally at least one selected from the group consisting of 0-10% of MgO, 0-5% of CaO, and 0-5% of SrO, such that BaO+MgO+CaO+SrO is 25-40%, and optionally at least one selected from the group consisting of 0.01-1% of Sb 2 O 3 , 0.01-1% of SnO 2 , and 0.01-1% of As 2 O 3 wherein SiO 2 +B 2 O 3 is 47-58%; Li 2 O+Na 2 O+K 2 O is 6-14%; and the optical glass has an Abbe number v d of 58-65.