Optical glass, glass material for press molding, optical element blank, optical element and manufacturing method thereof

摘要

A fluorophosphate glass containing: P5+ in an amount of 20 to 45 cationic %; Al3+ in an amount of 15 to 35 cationic %; Ba2+ in an amount of 20 to 50 cationic %; F− in an amount of 20 to 50 anionic %; and O2− in an amount of 50 to 80 anionic %. A molar ratio of O2−/P5+ is larger than or equal to 3.5. In addition, a molar ratio of Al3+/P5+ is larger than or equal to 0.45. Furthermore, the Abbe number (&ngr;d) of the glass is larger than or equal to 66. Finally a refractive index (nd) of the glass satisfies an expression (1): nd≧2.0614−0.0071×&ngr;d.