| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a high refractive index-lower to middle dispersion type optical glass composition that has nd within a high refractive index range of 1.83-1.87 andνd within a range of 43-47, and yet shows excellent melting property, processability (droplet property), crystallinity and the like. <P>SOLUTION: The optical glass composition contains, in % by mole, 5.0-25.0% SiO<SB>2</SB>, 20.0-40.0% B<SB>2</SB>O<SB>3</SB>, 0-15.0% ZnO, 0-5.0% ZrO<SB>2</SB>, 10.0-25.0% La<SB>2</SB>O<SB>3</SB>, 0-5.0% Ta<SB>2</SB>O<SB>5</SB>and 5.0-20.0% Gd<SB>2</SB>O<SB>3</SB>, satisfies a molar ratio of SiO<SB>2</SB>/B<SB>2</SB>O<SB>3</SB>of 0.25-0.90, does not substantially contain Li<SB>2</SB>O, and has a refractive index (nd) to the d-line of 1.83-1.87, an Abbe number (νd) to the d-line of 43-47 and a liquidus temperature of≤1,300°C. A preform and an optical element are also provided. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
