| 摘要 |
PROBLEM TO BE SOLVED: To provide a lead-free optical glass having refractive index (nd) of 1.65-1.75, Abbe number (νd) of≥45 and high weather resistance and suitable for mold press molding. SOLUTION: The optical glass for mold press molding has refractive index (nd) of 1.65-1.75, Abbe number (νd) of≥45 and≤650°C softening point and contains no lead and comprises B<SB>2</SB>O<SB>3</SB>-La<SB>2</SB>O<SB>3</SB>-ZnO-Gd<SB>2</SB>O<SB>3</SB>-based glass being≥20°C inΔT=ämolding temperature (in 10<SP>1.0</SP>poise)-liquid phase temperature},≤0.2% weight loss in the water resistance test by a powder method of the Japan Optical Glass Industry Standard (JOGIS) and≤1.2% in the weight loss in the acid resistance test by the powder method. COPYRIGHT: (C)2007,JPO&INPIT
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