| 摘要 |
PROBLEM TO BE SOLVED: To provide a new optical glass, which is a B<SB>2</SB>O<SB>3</SB>-TeO<SB>2</SB>-La<SB>2</SB>O<SB>3</SB>-based glass composition, is excellent in devitrification resistance, has optical constants such as a refractive index and an Abbe number which are required for an aspherical lens and the like, and has a low glass transition point, and thus is suitable for precision press molding. SOLUTION: The optical glass comprises, by mol% in terms of oxides, 30-60% B<SB>2</SB>O<SB>3</SB>, 0.2-50% TeO<SB>2</SB>, and La<SB>2</SB>O<SB>3</SB>. Preferablly, the glass comprises 1-35% La<SB>2</SB>O<SB>3</SB>and less than 1% WO<SB>3</SB>and Ga<SB>2</SB>O<SB>3</SB>respectively. The glass has a refractive index (nd) of 1.80-2.10, an Abbe number (νd) of 16-36 as the optical constants and a glass transition point (Tg) of 680°C or lower. COPYRIGHT: (C)2009,JPO&INPIT
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