| 摘要 |
An optical glass composition contains, in % by weight, 1.0% or more and 12.0% or less of SiO2, 8.0% or more and 18.0% or less of B2O3, 0% or more and 6.0% or less of ZnO, 1.0% or more and 10.0% or less of ZrO2, 25.0% or more and 47.0% or less of La2O3, 0% or more and 5.0% or less of R2O (here, R is at least one of Li, Na and K), 0% or more and 15.0% or less of Nb2O5, 0% or more and 7.0% or less of TiO2, 0% or more and 15.0% or less of Ta2O5, 1.0% or more of Nb2O5+TiO2+Ta2O5, 0% or more and 25.5% or less of Gd2O3, 0.5% or more and 15.0% or less of WO3 and 0.5% or more and 26.0% or less of Gd2O3+WO3, and has nd of 1.88 or higher and 1.92 or lower and &ngr;d of 33 or higher and 37 or lower, and a preform and an optical element are formed from the optical glass composition.
|
