Patent ID: 8563451

Claim:
An optical glass, comprising 25 to 60 mol % B 2 O 3 , 10 to 35 mol % of La 2 O 3 , a total of 2 to 45 mol % TiO 2 and/or Nb 2 O 5 , 2 to 25 mol % WO 3 , and 1 to 40 mol % ZnO, a total of 20 mol % or less of RO, a total of 2.5 mol % or less of Rn 2 O, and comprising no GeO 2 , Gd 2 O 3 or Ga 2 O 3 , in terms of their oxides and having a refractive index (nd) of 1.78 to 2.2 and an Abbe number (νd) of 16 to less than 40, and where R is one or more selected from the group consisting of Ba, Sr, Ca, and Mg, and Rn is one or more selected from the group consisting of Li, Na, K and Cs.