Multilayered interference pigments

US6656259B2 · kind B2 · utility

Assignee

• MERCK PATENT GESELLSCHAFT MIT BESHRANK TER HAFTUNG · DE

Inventors

• Gerhard Pfaff · Mainburg, DE
• Helge Kniess · Roßdorf, DE
• Peter Reynders · Griesheim, DE

Key dates

• Filing date: Aug 2, 2002
• Grant date: Dec 2, 2003
• Expiry date: Aug 2, 2022

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/2993
• WIPO field: Pharmaceuticals
• WIPO sector: Chemistry

Abstract

The invention relates to multilayered interference pigments which comprise a platelet-shaped substrate of silicon dioxide which is coated alternately with layers of light-transparent materials having refractive indices of n>1.8 and layers of light-transparent materials having refractive indices of n≦1.8, where the optical thickness of the platelet-shaped substrate and the optical thickness of the individual layers of light-transparent materials having refractive indices of n≦1.8 are the same.