| 摘要 |
PROBLEM TO BE SOLVED: To provide optical glass which has high dispersion property, is also suitable for high-order achromatic doublet, and has excellent glass stability.SOLUTION: An optical glass includes, by mass, 12 to 40% of SiO, ≥15% and <42% of NbO, ≥2% and <18% of TiO(wherein, NbO/TiOis >0.6), 0.1 to 20% of LiO, 0.1 to 15% of NaO and 0.1 to 25% of KO, and has an Abbe number &ngr;d of 20 to 30, a &Dgr;Pg, F of ≤0.016 and a liquid phase temperature of ≤1,200°C. |
