Phototropic glass with a refractive index of at least 1.59

US4486541A · kind A · utility

Assignee

• Schott Glaswerke · DE

Inventors

• George Gliemeroth · Ingelheim am Rhein, DE
• Uwe Eichhorn · Großerkmannsdorf, DE

Key dates

• Filing date: Dec 8, 1983
• Grant date: Dec 4, 1984
• Expiry date: Dec 8, 2003

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C03C4/06
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A phototropic glass with an optical position n.sub.d .ltoreq.1.59 and v.sub.d .gtoreq.40 and with a density of .ltoreq.3.2 g/cm.sup.3 is described for the first time. Its composition lies within the system of EQU SiO.sub.2 --R.sub.2 O.sub.3 --R.sub.2 O--RO--RO.sub.x --R.sub.2 O.sub.5, PA1 wherein R.sub.2 O.sub.3 is Al.sub.2 O.sub.3, B.sub.2 O.sub.3 and rare earth oxides; R.sub.2 O is alkali metal oxides; RO is alkaline earth metal oxides, ZnO, SnO, or PbO; RO.sub.x is GeO.sub.2, ZrO.sub.2, TiO.sub.2, or WO.sub.3 ; and R.sub.2 O.sub.5 is Nb.sub.2 O.sub.5, Ta.sub.2 O.sub.5, or P.sub.2 O.sub.5.