| 摘要 |
An optical glass suitable for mold forming having a metal composition in wt % in terms of metal oxides calculated from the composition of the following components: P<SUB>2</SUB>O<SUB>5 </SUB>34-50%, Li<SUB>2</SUB>O 2-9%, Na<SUB>2</SUB>O 7-28%, K<SUB>2</SUB>O 3-27%, provided that the total of R<SUB>2</SUB>O is 17-41% (R: Li, Na, K), Al<SUB>2</SUB>O<SUB>3 </SUB>6.5-30%, ZnO 0-22%, BaO 0-21%, SrO 0-18%, CaO 0-16%, MgO 0-14%, provided that the total of R'O is 0-34% (R': Zn, Ba, Sr, Ca, Mg), ZrO<SUB>2 </SUB>0-1.5% and F 1.5-32% relative to the total weight of the oxides, and exhibits a glass transition temperature (Tg) of 350° C. or lower and a specific gravity (Sg) of 3.1 or less and is excellent in chemical durability. The optical glass can be press formed at a low temperature of about 270 to 400° C.
|
