Optical glass, glass molded body, optical device and their production methods
AssigneeHoya Corporation
InventorsYuta Kobayashi, Yoichi Hachitani, Yunoshin Kanayama
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Abstract
An optical glass comprising, by mass %, 12 to 30% of total of B2O3 and SiO2, 55 to 80% of total of La2O3, Gd2O3, Y2O3, Yb2O3, ZrO2, Nb2O5 and WO3, 2 to 10% of ZrO2, 0 to 15% of Nb2O5, 0 to 15% of ZnO and 0% or more but less than 13% of Ta2O5, wherein the ratio of the content of Ta2O5 to the total content of La2O3, Gd2O3, Y2O3, Yb2O3, ZrO2, Nb2O5 and WO3 is 0.23 or less, the ratio of the total content of La2O3, Gd2O3, Y2O3 and Yb2O3 to the total content of B2O3 and SiO2 is from 2 to 4, the optical glass having a refractive index nd of 1.86 or more and an Abbe's number νd of 38 or more, and a rod-shaped glass shaped material and an optical element formed of the above optical glass each.
Claims9
An optical glass comprising, by mass %,
- 12 to 30% of total of B2O3 and SiO2,
- 0 to 17% B2O3,
- 55 to 80% of total of La2O3, Gd2O3, Y2O3, Yb2O3, ZrO2, Nb2O5 and WO3,
- 2 to 10% of ZrO2,
- 0 to 15% of Nb2O5,
- 0 to 12% of ZnO,
- 0% or more but less than 13% of Ta2O5, and
- 0 to 0.2% Li2O,
- 0 to 5% BaO,
- the optical glass containing no Pb,
- wherein the ratio of the content of Ta2O5 to the total content of La2O3, Gd2O3, Y2O3, Yb2O3, ZrO2, Nb2O5 and WO3 is 0.23 or less,
- the ratio of the total content of La2O3, Gd2O3, Y2O3 and Yb2O3 to the total content of B2O3 and SiO2 is from 2 to 3.6,
- the optical glass having a refractive index nd of 1.86 or more and an Abbe's number νd of 38 or more.
Dependencies are inferred from the claim text.