| 摘要 |
The present invention relates to optical glass capable of reducing production cost, such as cost of materials, and having excellent melting property and thermal stability, low-temperature softening property and a high refraction index and low dispersion. The present invention provides optical glass which is oxide glass having a combined content of [B^(3+) + Si^(4+) + La^(3+) + Gd^(3+) + Y^(3+) + Yb^(3+)] of 65% or more as expressed in terms of cation%, a cation ratio of 0.30-0.70, a cation ratio less than 1 (not including 0), a combined content [Nb^(5+) + Ti^(4+) + W^(6+) + Ta^(5+) + Bi^(3+)] less than 7% and a cation ratio of 0.5 or more, wherein L is 24 or more, Abbe number d is 43.5-47, and refraction index nd to the Abbe number d satisfies formula (1) of nd >= 2.25 - 0.01 d. |
