| 摘要 |
PURPOSE: An optical glass, a glass material for press molding made of the optical glass, an optical device made of the optical glass and its preparation method are provided, to prepare a press molded article from an optical glass having a high refractive index and a high dispersion without devitrification. CONSTITUTION: The optical glass comprises greater than or equal to 18 wt% and less than 30 wt% of SiO2; greater than or equal to 12 wt% and less than 23 wt% of BaO; 22-37 wt% of TiO2; greater than or equal to 7 wt% and less than 16 wt% of Nb2O5; 5-20 wt% of Na2O; 0-6 wt% of K2O; 0-5 wt% of CaO; 0-5 wt% of SrO; 0-4 wt% of ZrO2; 0-3 wt% of Ta2O5; 0-1 wt% of Sb2O5; and greater than or equal to 0 wt% and less than 0.5 wt% of P2O5, and essentially does not contain PbO, As2O3 and F. The optical glass has a refractive index of 1.80 or more and an Abbe number (vd) of 30 or less.
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