| 摘要 |
An optical glass comprising, by mol %, 0.1 to 40% of SiO2, 10 to 50% of B2O3, 0 to 10% of total of Li2O, Na2O and K2O, 0 to 10% of total of MgO, CaO, SrO and BaO, 0.5 to 22% of ZnO, 5 to 50% of La2O3, 0.1 to 25% of Gd2O3, 0.1 to 20% of Y2O3, 0 to 20% of Yb2O3, 0 to 25% of ZrO2, 0 to 25% of TiO2, 0 to 20% of Nb2O5, 0 to 10% of Ta2O5, over 0.1% but not more than 20% of WO3, 0 to less than 3% of GeO2, 0 to 10% of Bi2O3, and 0 to 10% of Al2O3, the mass ratio of the content of SiO2 to the content of B2O3, SiO2/B2O3, being 1 or less, the optical glass having a refractive index nd of 1.86 to 1.95 and an Abbe's number nud of (2.36-nd)/0.014 or more but less than 38.
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