| 摘要 |
<p>An optical glass comprising, in terms of percent by weight, 25 to less than 45% P2O5, 6 to 20% B2O3, 24 to less than 40% BaO, 3 to 14% ZnO, 0 to 15% MgO, 0 to 15% CaO, 0 to 15% SrO, 0 to 5% Li2O, 0 to 5% Na2O, 0 to 5% K2O, 0 to 5% WO3, and 0 to 5% Al2O3. Preferably, the amount of WO3 is 0.1 to 5%, that of MgO is 3.6 to 15%, that of Li2O+Na2O+K2O is 0.1 to 5%, the ZnO/BaO weight ratio is from 0.12 to less than 0.50, the amount of Sb2O3+As2O3 is 0 to less than 0.5%, and the glass has a refractive index (nd) of 1.54 to 1.65, an Abbe's number (νd) of larger than 57 and not larger than 69, and a liquidus temperature in the range of from 870°C to 930°C. The optical glass has excellent devitrification resistance, an intermediate refractive index, and low dispersion. It can be mass-produced at a relatively low material cost because it contains no ingredients formed from significantly expensive raw materials, such as Ta2O5.</p> |
