Lead-free optical light flint glass materials

US6551952B2 · kind B2 · utility

Assignee

• Schott Glas · DE

Inventors

• Silke Wolff · Hückeswagen, DE
• Peter Brix · Mainz, DE
• Ute Woelfel · Bingen, DE

Key dates

• Filing date: Nov 29, 2000
• Grant date: Apr 22, 2003
• Expiry date: Feb 1, 2021

Classification

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

Abstract

The lead-free optical light flint glass material has a refractive index nd between 1.54 and 1.61 and an Abbe number &ngr;d of between 38 and 45. It has a composition, based on oxide content, of SiO2 from 52 to 62% by weight, Al2O3 from 3 to 8% by weight, Na2O from 7 to 14% by weight, K2O from 8 to 14% by weight, TiO2 from 13 to 18% by weight, ZrO2 from 0 to 5% by weight, with at least one refining agent, if needed, in an amount suitable for the purposes of refining; and with the proviso that a sum total of Na2O and K2O present is greater than 18% by weight.