| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide optical glass with excellent devitrification resistance and a high refractive index, a glass molding and a glass molding comprising the optical glass. <P>SOLUTION: The optical glass comprises, in mass%: 12-30% for the total amount of B<SB>2</SB>O<SB>3</SB>and SiO<SB>2</SB>; 55-80% for the total amount of La<SB>2</SB>O<SB>3</SB>, Gd<SB>2</SB>O<SB>3</SB>, Y<SB>2</SB>O<SB>3</SB>, Yb<SB>2</SB>O<SB>3</SB>, ZrO<SB>2</SB>, Nb<SB>2</SB>O<SB>5</SB>and WO<SB>3</SB>; 2-10% of ZrO<SB>2</SB>; 0-15% of Nb<SB>2</SB>O<SB>5</SB>, 0-15% ZnO, and 0-<13% Ta<SB>2</SB>O<SB>5</SB>; wherein the ratio of the amount of Ta<SB>2</SB>O<SB>5</SB>to the total amount of La<SB>2</SB>O<SB>3</SB>, Gd<SB>2</SB>O<SB>3</SB>, Y<SB>2</SB>O<SB>3</SB>, Yb<SB>2</SB>O<SB>3</SB>, ZrO<SB>2</SB>, Nb<SB>2</SB>O<SB>5</SB>and WO<SB>3</SB>is at most 0.23; the ratio of the total amount of La<SB>2</SB>O<SB>3</SB>, Gd<SB>2</SB>O<SB>3</SB>, Y<SB>2</SB>O<SB>3</SB>and Yb<SB>2</SB>O<SB>3</SB>to the total amount of B<SB>2</SB>O<SB>3</SB>and SiO<SB>2</SB>is 2-4; the refractive index nd is at least 1.86; and the Abbe's number νd is at least 38. The rod-shaped glass molding and the glass molding comprise the above optical glass. <P>COPYRIGHT: (C)2008,JPO&INPIT |
