| 摘要 |
PROBLEM TO BE SOLVED: To provide optical glass having a low glass transition temperature and yielding point and suitable to precision press molding, in optical glass having a high refractive index and low dispersibility. SOLUTION: This optical glass for presision press molding has a basic composition of SiO<SB>2</SB>-B<SB>2</SB>O<SB>3</SB>-La<SB>2</SB>O<SB>3</SB>-Gd<SB>2</SB>O<SB>3</SB>-Li<SB>2</SB>O-Ta<SB>2</SB>O<SB>5</SB>-BaO-ZnO, and has optical constants of a refractive index (nd) ranging from 1.72 to 1.75 and an Abbe number (νd) ranging from 49.0 to 52.0 and a glass transition temperature (Tg) of≤540°C and also a yielding point (At) of≤580°C. COPYRIGHT: (C)2007,JPO&INPIT
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