| 摘要 |
<p>The present invention relates to an optical glass containing, in terms of mass % on the basis of oxides, B2O3: 10 to 20%, SiO2: 0.5 to 12%, ZnO: 5 to 19%, Ta2O5: 2.5 to 17%, Li2O: 0.2 to 3%, ZrO2: 0.6 to 4.9%, WO3: 1 to 20%, La2O3: 25 to 50%, Gd2O3: 0 to 13%, and Y2O3: 0.2 to 20%, provided that La2O3+Gd2O3+Y2O3 is 35 to 60%, in which the optical glass does not substantially contain Nb2O5, and has a refractive index (nd) of 1.82 to 1.86, an Abbe's number (νd) of 37 to 44 and a glass transition point (Tg) of 630° C. or lower.</p> |
