| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical glass having high refractive index and high dispersion characteristic and suitable for precision press molding, a preform for precision press molding and its manufacturing method, and an optical element comprising the optical glass and its manufacturing method. SOLUTION: This optical glass for precision press molding contains P<SB>2</SB>O<SB>5</SB>, Nb<SB>2</SB>O<SB>5</SB>, WO<SB>3</SB>, TiO<SB>2</SB>, Bi<SB>2</SB>O<SB>3</SB>, Li<SB>2</SB>O, and Na<SB>2</SB>O as essential components, and B<SB>2</SB>O<SB>3</SB>, BaO, ZnO, K<SB>2</SB>O, Sb<SB>2</SB>O<SB>3</SB>, and As<SB>2</SB>O<SB>3</SB>as arbitrary components, and the content of the Bi<SB>2</SB>O<SB>3</SB>is 0.5-15 mol%, the total content of Nb<SB>2</SB>O<SB>5</SB>, WO<SB>3</SB>, TiO<SB>2</SB>, and Bi<SB>2</SB>O<SB>3</SB>is 25-45 mol%, the total content of Li<SB>2</SB>O, Na<SB>2</SB>O and K<SB>2</SB>O is not greater than 42 mol%, and the total of the essential components and the arbitrary components is not lower than 98 mol%, and refractive index (nd) is 1.75-2.0, and Abbe number (νd) is 18-30. This preform for precision press molding comprises this optical glass. In this molding method of preform for press molding made from the optical glass comprising the above-mentioned weight composition, a molten glass gob of a specified weight is separated from the discharging molten glass. This optical element comprises the optical glass. In this manufacturing method of the optical element, the preform for press molding manufactured by the preform for press molding or the above-mentioned manufacturing method, is heated and precision press molded. COPYRIGHT: (C)2005,JPO&NCIPI
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