Patent ID: 7892998

Claim:
An optical glass comprising, based on a total weight of the optical glass: 15 to 40 weight percent of P 2 O 5 ; 0 to 10 weight percent of Li 2 O; 0 to 20 weight percent of Na 2 O; 0 to 20 weight percent of K 2 O; more than 2 weight percent and not more than 15 weight percent of TiO 2 ; 0 to 15 weight percent of CaO; 0 to 32 weight percent of BaO; 0 to 0.8 weight percent of SrO; 0 to 4 weight percent of ZnO; 0 to less than 3 weight percent of Bi 2 O 3 ; 0 to 31.5 weight percent of Nb 2 O 5 ; 0 to less than 20 weight percent of WO 3 ; and 0 to 1 weight percent of Sb 2 O 3 , wherein a total weight of Li 2 O, Na 2 O and K 2 O is in a range of 3 to 30 weight percent based on the total weight of the optical glass, the optical glass does not comprise B 2 O 3 , SiO 2 , Al 2 O 3 , and MgO, and a glass transition temperature Tg of the optical glass is not higher than 540° C.