High refractive index glasses, multifocal corrective lenses containing same

US6196684A · kind A · utility

Assignee

• Corning S.A. · FR

Inventors

• Marie M. J. Comte · Fontenay-aux-Roses, FR
• Paulo Gaspar Jorge Marques · Vaux-le-Pénil, FR

Key dates

• Filing date: Jun 2, 2000
• Grant date: Mar 6, 2001
• Expiry date: Jun 2, 2020

Classification

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

Abstract

The present invention relates to glasses of high refractive index having the following composition of oxides, expressed in percentages by weight: SiO.sub.2 27-36 B.sub.2 O.sub.3 0-9 Li.sub.2 O 1-5 Na.sub.2 O 1-7 K.sub.2 O 0-7 CaO 0-7 BaO 4-13 ZnO 0-8 La.sub.2 O.sub.3 4-15 PbO 4-27 TiO.sub.2 7-18 ZrO.sub.2 0-9 Nb.sub.2 O.sub.5 0-8 with: Li.sub.2 O + Na.sub.2 O + K.sub.2 O 6-15 SiO.sub.2 + TiO.sub.2 + ZrO.sub.2 42-55 PbO + TiO.sub.2 + ZrO.sub.2 + Nb.sub.2 O.sub.5 29-40; their use for the production of segments for multifocal corrective lenses; and multifocal corrective lenses incorporating at least one such segment in their structure.