| 摘要 |
PROBLEM TO BE SOLVED: To provide a novel optical glass that has a high diffraction index and that has a low dispersion characteristic, and to provide a production process therefor.SOLUTION: Provided is: an optical glass containing, in mole%, LaO20 to 60%, AlO0 to 60% (not including 0%), TaO0 to 50% (not including 0%), and SiO0 to 10% (not including 10%); furthermore an optical glass containing, in mole%, NbO0 to 40%, GdO0 to 20%, ZrO0 to 20%, TiO0 to 20%, YO0 to 20%, or YbO0 to 20%, and in which the diffraction index (nd) is 1.80 to 2.10, and the Abbe number (νd) is 20 to 47; and a production process for producing glass material by heat-melting a glass raw-material mass in a state of being floated and held, to produce a molten glass, followed by cooling the molten glass.SELECTED DRAWING: Figure 1 |
