| 摘要 |
An embodiment of the present invention relates to an optical glass which is an oxide glass having Si4+, B3+, La3+, Ti4+, Nb5+, and Zr4+ as essential components, and including, in terms of cation%, a total of 5-55% of Si4+ and B3+, 10-50% of La3+ (La3+, Gd3+, Y3+, and Yb3+ being 70% or less in total), and a total of 22-25% of Ti4+, Nb5+, Ta5+, and W6+, the content of Ti4+ being 22% or less, [Si4+/(Si4+ + B3+)] being 0.40 or less, the total content of La3+, Gd3+, Y3+, Yb3+, Zr4+, Ti4+, Nb5+, Ta5+, W6+, and Bi3+ being at least 65%, [Y3+/(La3+ + Gd3+ + Y3+ + Yb3+)] being 0.12 or less, [Ba2+/(La3+ + Gd3+ + Y3+ + Yb3+)] being 0.40 or less, [(Zr4+ + Ti4+ + Nb5+ + Ta5+ + W6+)/Zr4+] being at least 2, (Ti4+/B3+) being at least 0.85, and the optical glass having an Abbe number &ngr;d in the range of 23-25 and a refractive index nd satisfying the expression nd ≥ 2.205 – (0.0062 × &ngr;d). |
