| 摘要 |
An optical glass of the present invention has optical constants of a refractive index (nd) within a range from 1.75 to 1.85 and an Abbe number (nu d) within a range from 35 to 45, comprises SiO2 and B2O3 as essential components and one or more components selected from the group consisting of ZrO2, Nb2O5, Ta2O5 and WO3, has a glass transition temperature (Tg) of 580° C. or below and has weathering resistance (surface method) of Class 1 or Class 2.
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