| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical glass having refraction index (nd) and Abbe number (νd) in a desired range and high refractive low dispersion region, excellent in transmissivity and having high thermal stability even without containing large amounts of TaOand NbO.SOLUTION: There is provided an optical glass containing, based on the total mass of the glass with oxide conversion composition, by mass%, LaOof 10.0 to 40.0%, BOof 10.0 to 40.0%, SiOof 0 to 15.0%, NbOof 0 to 20.0%, TiOof 0 to 10.0%, TaOof 0 to 10.0%, ZrOof 15% or less, BaO of 9% or less and WOof 1% or less and having mass ratio with oxide conversion composition (NbO+TiO)/(SiO+BO) of 0.3 to 1.0, refraction index (nd) of 1.75 to 1.95 and Abbe number (νd) of 30 to 40.SELECTED DRAWING: None |
