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US 8,741,795 B2Granted
Optical glass
AssigneeHoya Corporation
InventorsXuelu Zou, Yunoshin Kanayama, Tomoaki Negishi
Life of this patent
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Abstract
An optical glass having high-refractivity and low-dispersion properties and containing, by mol %, 0.1 to 40% of SiO2, 10 to 50% of B2O3, wherein the mass ratio of the content of SiO2 to the content of B2O3, SiO2/B2O3, is 1 or less, 0.5 to 22% of ZnO, 5 to 50% of La2O3, and optionally other ingredients. The optical glass has a refractive index nd of 1.86 to 1.95 and an Abbe's number νd of (2.36−nd)/0.014 or more but less than 38, and a glass transition temperature of equal to or greater than 640° C.
Claims21
An optical glass comprising, by mol %,
- 0.1 to 40% of SiO2,
- 10 to 50% of B2O3,
- 0 to 10% of total of Li2O, Na2O and K2O,
- 0 to 10% of total of MgO, CaO, SrO and BaO,
- 0.5 to 22% of ZnO,
- 5 to 50% of La2O3,
- 0.1 to 25% of Gd2O3,
- 0.1 to 20% of Y2O3,
- 0 to 20% of Yb2O3,
- 0 to 25% of ZrO2,
- 0 to 25% of TiO2,
- 0 to 20% of Nb2O5,
- 0 to 7% of Ta2O5,
- over 0.1% but not more than 20% of WO3,
- 0 to less than 3% of GeO2,
- 0 to 10% of Bi2O3, and
- 0 to 10% of Al2O3,
- the mass ratio of the content of SiO2 to the content of B2O3, SiO2/B2O3, being 1 or less, the optical glass having a refractive index nd of 1.86 to 1.95, an Abbe's number νd of (2.36−nd)/0.014 or more but less than 38, and a glass transition temperature of equal to or greater than 640° C.
15 more elements
Dependencies are inferred from the claim text.