Lead-free optical glasses

US6333288A · kind A · utility

Assignee

• Schott Glas · DE

Inventors

• Marc Clement · Mainz, DE
• Silke Wolff · Hückeswagen, DE
• Magdalena Winkler-Trudewig · Mainz, DE

Key dates

• Filing date: May 8, 2000
• Grant date: Dec 25, 2001
• Expiry date: May 8, 2020

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S501/903
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

The invention can relate to essentially lead-free optical glasses having a refractive index n.sub.d of from about 1.65 to about 1.87 and an Abbe number .nu..sub.d of from about 27 to about 43 and a composition (in % by weight, based on oxide) of SiO.sub.2 about 10-about 25, B.sub.2 O.sub.3 >about 10-about 25, Na.sub.2 O about 2.5-about 10, K.sub.2 O 0-about 3, CaO about 0.5-about 5, BaO about 15-about 30, ZnO about 5-about 15, TiO.sub.2 about 6-about 15, ZrO.sub.2 about 0.5-about 8, Y.sub.2 O.sub.3 about 0.1-about 2, La.sub.2 O.sub.3 about 0.5-about 8, Nb.sub.2 O.sub.5 about 6-about 12, with La.sub.2 O.sub.3 +Nb.sub.2 O.sub.5.ltoreq.about 17,Ta.sub.2 O.sub.5 0-about 1, and Gd.sub.2 O.sub.3 0-about 1.