| 摘要 |
An optical glass is oxide glass wherein Si4++B3+ ranges from 10-60 cation %, La3++Gd3++Y3++Yb3+ ranges from 25-70 cation %, Ti4++Nb5++W6++Bi3+ ranges from 10-20 cation %, Li+ content ranges from 0-5.0 cation %, Ge content is lower than 5.0 mass % as quantity of GeO2 based on oxides, no Pb included, a cation ratio, Si4+/B3+, is equal or lower than 0.70, a cation ratio, (La3++Gd3++Y3++Yb3+)/(Ti4++Nb5++W6++Bi3+), ranges from 1.90-7.00, a cation ratio, Y3+/(La3++Gd3++Y3++Yb3+), is equal or lower than 0.180, and Nb5+ is an essential component, with Ti4+/Nb5+ being equal or lower than 4.00, with nd of higher than 1.920 and equal or lower than 2.000, vd ranging from 28.0-34.0, and yield point higher than 645° C., and a deviation &Dgr;Pg,F from normal line of partial dispersion ratio Pg,F being equal or lower than 0.0005. |
