| 摘要 |
An optical glass, characterized in that it comprises, mass % in terms of oxides, 30 to 55 % of SiO2, 0.5 to 10 % of ZrO2, 20 to 50 % of Nb2O5, 0 to 15 % of Ta2O5, 0 to 25 % of Li2O, 0 to 25 % of Na2O, 0 to 25 % of K2O, provided that the sum of Li2O, Na2O and K2O is 12 to 25 %, less than 5 % of MgO, less than 5 % of CaO, less than 5 % of SrO, less than 5 % of BaO, less than 5 % of ZnO, provided that the sum of MgO, CaO, SrO, BaO, and ZnO is less than 5 %, and 0 to 1 % of Sb2O3; and an optical element using the optical glass. The optical glass has optical constants including a refractive index (nd) of 1.60 to 1.78 and an Abbe value ( nu d) of 29 to 45, has a great negative anomalous dispersion, and is excellent in chemical durability and in homogeneity. Further, it contains none of components such as PbO which require some cost for environmental pollution control and also does not contain, as an essential component, GeO2 or Ta2O5 which needs a high material cost.
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