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US 4,732,875 AGranted
Optical glass
AssigneeHoya Corporation
InventorKoji Sagara
Life of this patent
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AssigneeHoya Corporation
InventorKoji Sagara
Estimating the term…
To tellurite optical glass comprising TeO.sub.2, high valence components are added and may be a combination of La.sub.2 O.sub.3, at least one of B.sub.2 O.sub.3 and GeO.sub.2, and at least one of Ta.sub.2 O.sub.5 and Nb.sub.2 O.sub.5. The high valence components may include Y.sub.2 O.sub.3, Gd.sub.2 O.sub.3, and Yb.sub.2 O.sub.3. Amounts of TeO.sub.2 and La.sub.2 O.sub.3 are restricted to ranges between 10% and 80% and between 5% and 35%, respectively. A sum of B.sub.2 O.sub.3 and GeO.sub.2 must fall within a range between 1% and 30%, with an amount of GeO.sub.2 restricted between 0% and 22%. A total of La.sub.2 O.sub.3, Y.sub.2 O.sub.3, Gd.sub.2 O.sub.3, and Yb.sub.2 O.sub.3 must be between 5% and 50%. A sum of Ta.sub.2 O.sub.5 and Nb.sub.2 O.sub.5 should range from 1% to 26%, with individual amounts of Ta.sub.2 O.sub.5 and Nb.sub.2 O.sub.5 kept between 0% and 20% and between 0% and 26%, respectively.
Optical glass consisting essentially of, by weight, 10-80% of TeO.sub.2, 7.9-30% of B.sub.2 O.sub.3, 0-22% of GeO.sub.2, 5-35% of La.sub.2 O.sub.3, 0-18% of Y.sub.2 O.sub.3, 0-25% of Gd.sub.2 O.sub.3, 0-15% of Yb.sub.2 O.sub.3, 0-20% of Ta.sub.2 O.sub.5, and 0-26% of Nb.sub.2 O.sub.5, a first sum of B.sub.2 O.sub.3 and GeO.sub.2, a second sum of La.sub.2 O.sub.3, Y.sub.2 O.sub.3, Gd.sub.2 O.sub.3, and Yb.sub.2 O.sub.3, and a third sum of Ta.sub.2 O.sub.5 and Nb.sub.2 O.sub.5 being between 7.9% and 30%, between 5% and 50%, and between 1% and 26%, respectively.
Optical glass consisting essentially of, by weight, 20-75% of TeO.sub.2, 7.9-30% of B.sub.2 O.sub.3, 0-12% of GeO.sub.2, 6-30% of La.sub.2 O.sub.3, 0-15% of Y.sub.2 O.sub.3, 0-18% of Gd.sub.2 O.sub.3, 0-12% of Yb.sub.2 O.sub.3, 0-18% of Ta.sub.2 O.sub.5, 0-22% of Nb.sub.2 O.sub.5, 0-6% of ZrO.sub.2, 0-6% of HfO.sub.2, and 0-25% of ZnO, a first sum of B.sub.2 O.sub.3 and GeO.sub.2, a second sum of La.sub.2 O.sub.3, Y.sub.2 O.sub.3, Gd.sub.2 O.sub.3, and Yb.sub.2 O.sub.3, and a third sum of Ta.sub.2 O.sub.5 and Nb.sub.2 O.sub.5 being between 7.9 and 30%, between 6% and 35%, and between 2% and 22%, respectively.
Dependencies are inferred from the claim text.