Lead-free optical heavy flint glasses

US6709998B2 · kind B2 · utility

Assignee

• Schott Glas · DE

Inventors

• Silke Wolff · Hückeswagen, DE
• Ute Woelfel · Bingen, DE

Key dates

• Filing date: Jul 10, 2002
• Grant date: Mar 23, 2004
• Expiry date: Jul 10, 2022

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C03C3/062
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

The invention relates to lead-free optical glasses which have refractive indices nd of between 1.65 and 1.80 and Abbe numbers &ngr;d of between 21 and 33 and possess the following composition (in % by weight, based on oxide): SiO2 27-40; B2O3 0-<0.5; Al2O3 0-6; Na2O 7-18; K2O 1-10; BaO 1-10; SrO 0-3; CaO 0.5-5; MgO 0-3; with BaO+SrO+CaO+MgO<15; TiO2 21-37; ZrO2 0-7; Nb2O5 5-17; WO3 0.1-7.