| 摘要 |
The present invention provides an optical glass having low-dispersion properties, a very high refractive index and excellent glass stability, and is less susceptible to coloring. The optical glass, which is an oxide glass, comprises, represented by cation %, 0 to 30% of Si^4+, 10 to 55% of B^3+, less than 5% of the sum of Li^+, Na^+ and K^+, less than 5% of the sum of Mg^2+, Ca^2+ and Sr^2+, 0 to 8% of Ba^2+, 0.1 to 15% of Zn^2+, 10 to 50% of La^3+, 0 to 20% of Gd^3+, 0 to 15% of Y^3+, 0 to 10% of Yb^3+, 0 to 20% of Zr^4+, 0.1 to 22% of Ti^4+, 0 to 20% of Nb^5+, 0 to 8% of Ta^5+, 0 to 5% of W^6+, 0 to 8% of Ge^4+, 0 to 10% of Bi^3+, and 0 to 10% of Ai^3+, wherein the cationic ratio of a content of Si^4+ to a content of B^3+, Si^4+/B^3+, is less than 1.0 and a total content of Nb_2O_5 and Ta_2O_5 as oxides is less than 14 wt%. In addition, the optical glass has a refractive index nd of 1.92 to 2.2 and an Abbe′s number vd of 25 to 45. |
