| 摘要 |
PROBLEM TO BE SOLVED: To provide optical glass with a high refractive index, having an extremely low glass transition temperature (Tg), and excellent in chemical durability thereby suitable to precision press forming. SOLUTION: This optical glass has a refractive index (nd) of 1.9 or above, an Abbe's number (νd) of 15 or above, and a glass transition point (Tg) of 300°C or lower which contains 50 mol% or more TeO<SB>2</SB>component and does not contain Pb and/or As compounds. The optical glass comprises an R<SB>2</SB>O component (R is one or more kinds selected from the group consisting of Li, Na, K and Cs), a ZnO component and a Bi<SB>2</SB>O<SB>3</SB>component, and further comprises Al<SB>2</SB>O<SB>3</SB>and/or Ga<SB>2</SB>O<SB>3</SB>component. COPYRIGHT: (C)2008,JPO&INPIT
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