abstract |
An optical glass comprising SiO<sub>2</sub>, B<sub>2</sub>O<sub>3</sub> and La<sub>2</sub>O<sub>3</sub> and one or more oxides selected from the group consisting of ZrO<sub>2</sub>, Nb<sub>2</sub>O<sub>5</sub> and Ta<sub>2</sub>O<sub>5</sub>, having a refractive index of 1.83 or over and an Abbe number of 35 or over and being free of F. |