Optical glasses
AssigneeCorning Glass Works
InventorsJean E. Boudot, Pascal A. J. Joly
Life of this patent
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Abstract
Glasses are disclosed that have a high refractive index on the order of 1.7 or greater, a low density on the order of 3 gm./cm..sup.3, good chemical durability and a dispersive index on the order of 40 or more. These glasses belong to a CaO--La.sub.2 O.sub.3 --TiO.sub.2 --B.sub.2 O.sub.3 --SiO.sub.2 family and are particularly useful in strong correction ophthalmic lenses and space optics.
Claims3
A glass having a composition within the CaO--La.sub.2 O.sub.3 --TiO.sub.2 --B.sub.2 O.sub.3 --SiO.sub.2 family and having a refractive index at least on the order of 1.7, a dispersive index at least on the order of 40, a density of about 3 g/cm.sup.3, and a weight loss, as measured in the AO test, of less than 5 mg/cm.sup.2, consisting essentially, as calculated in weight percent on the oxide basis, of about 18-28% CaO, 9-15% La.sub.2 O.sub.3, 9-15% TiO.sub.2, 30-54% B.sub.2 O.sub.3, and the remainder SiO.sub.2, the SiO.sub.2 content not exceeding 15% and the sum of B.sub.2 O.sub.3 + SiO.sub.2 being about 30-54%.
Dependencies are inferred from the claim text.