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US 10,370,289 B2Granted
Optical glass, preform, and optical element
AssigneeKabushiki Kaisha Ohara
InventorsKen Kikkawa, Atsushi Nagaoka
Life of this patent
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Abstract
An optical glass having a small partial dispersion ratio (θg,F), while having a refractive index (nd) and Abbe number (νd) within desired ranges, is obtained. The optical glass, in mass %, comprises 10.0 to 70.0% of an SiO2 component, 1.0 to 50.0% of an Nb2O5 component, and 1.0 to 30.0% of an Na2O component, and has a refractive index (nd) of 1.62 to 1.75, an Abbe number (νd) of 30 to 42, and a partial dispersion ratio (θg,F) of no greater than 0.594.
Claims10
An optical glass comprising, in mass %,
- 10.0 to 70.0% of an SiO2 component,
- more than 15.0% to 31% of an Nb2O5 component, and
- 1.0 to less than 20.0% of an Na2O component,
- a B2O3 component is no less than 7.99% and no more than 25.0%,
- a ZrO2 component is more than 1.0% and less than 15.0%,
- a BaO component is less than 15.0%,
- a Bi2O3 component is no more than 10.0%,
- a ZnO component is no more than 30.0%,
- a Li2O component is less than 5.0%,
- a mass ratio (Li2O+Na2O)/(ZrO2) of no less than 1.30,
- and having
- a refractive index (nd) of 1.62 to 1.75,
- an Abbe number (νd) of 30 to 42, and
- a partial dispersion ratio (θg,F) of no greater than 0.594.
11 more elements
Dependencies are inferred from the claim text.