| abstract |
The present invention relates to a B 2 O 3 —TeO 2 —La 2 O 3 -based glass composition having excellent devitrification resistance and optical constants (refractive index, Abbe number, etc.) required for an aspherical lens and the like. To provide a novel optical glass suitable for precision mold press molding having a low glass transition point. SOLUTION: It is characterized by containing 30 to 60% of B 2 O 3 , 0.2 to 50% of TeO 2 and La 2 O 3 in mol% based on oxide. Furthermore, WO 3 and Ga 2 O 3 are contained in less than 1% by mol% based on oxide, and La 2 O 3 is contained in 1 to 35% by mol% based on oxide. The optical glass has an optical constant of refractive index (nd) of 1.80 to 2.10, Abbe number (νd) of 16 to 36, and glass transition point (Tg) of 680 ° C. or lower. [Selection figure] None |