Lead and arsenic free optical lanthanum borate glass

US7638450B2 · kind B2 · utility

Assignee

• Schott AG · DE

Inventors

• Simone Monika Ritter · Mainz, DE
• Ute Woelfel · Bingen, DE
• Stefanie Hansen · Gensingen, DE

Key dates

• Filing date: Apr 27, 2006
• Grant date: Dec 29, 2009
• Expiry date: Apr 27, 2026

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C03C3/068
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

The lead-free, fluorine-free and arsenic-free optical glass, which is useful in mapping, projection, telecommunication, optical communication engineering, and mobile drive and laser technology, has a refractive index of 1.75≦nd≦1.83, an Abbe number of 34≦Vd≦44, and Tg≦560° C. The glass is free of WO3 and TeO2and has a composition in percent by weight based on oxide content of: SiO2, 0.5-8; B2O3, 10-25; ZnO, 10-22; La2O3, 23-34; Ta2O5, >15-25; Nb2O5, 0.5-15; Al2O3, 0-2; and can include optional ingredients, e.g. alkali and/or alkaline-earth oxides. In addition, a sum of B2O3 and ZnO is 33 to 41% by weight and preferably a sum of La2O3+Ta2O5+Nb2O5+Y2O3+ZrO2 is greater than 50% by weight.