Patent ID: 8008219

Claim:
An optical glass comprising, based on a total weight of the optical glass: not less than 35 weight percent and less than 45 weight percent of P 2 O 5 ; not less than 0.5 weight percent and less than 10 weight percent of B 2 O 3 ; 0 to 16 weight percent of Al 2 O 3 ; 0 to 2.5 weight percent of SiO 2 ; 0 to 26 weight percent of BaO; 0 to 20 weight percent of SrO; 23 to 38 weight percent of ZnO; more than 6 weight percent and not more than 20 weight percent of CaO; 0 to 16 weight percent of MgO; 0 or more weight percent and less than 1 weight percent of Li 2 O; 3 to 19 weight percent of Na 2 O; and 0 to 20 weight percent of K 2 O, wherein a total weight of BaO, SrO, ZnO, CaO, and MgO is not more than 55 weight percent based on the total weight of the optical glass, a total weight of Li 2 O, Na 2 O and K 2 O is not more than 24 weight percent based on the total weight of the optical glass, and a total content of P 2 O 5 , B 2 O 3 , Al 2 O 3 , SiO 2 , BaO, SrO, ZnO, CaO, MgO, Li 2 O, Na 2 O , K 2 O, TiO 2 , ZrO 2 and Ta 2 O 5 is not less than 99 weight percent based on the total weight of the optical glass.