Multilayer reflective film or pigment with viewing angle dependent reflection characteristics

US6641874B2 · kind B2 · utility

Assignee

• MERCK PATENT GESELLSCHAFT MIT BESHRANK TER HAFTUNG · DE

Inventors

• Matthias Kuntz · Seeheim-Jugenheim, DE
• Hans-Dieter Brueckner · Darmstadt, DE
• David Coates · Bishop's Stortford, GB
• Rodney Riddle · Holzminden, DE

Key dates

• Filing date: Mar 2, 2001
• Grant date: Nov 4, 2003
• Expiry date: Mar 2, 2021

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/24835
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

The invention relates to multilayer reflective films and pigments showing selective reflection of light wherein the reflection characteristics are dependent on the viewing angle, characterized in that they comprises at least one reflective layer, at least one circular polarizing layer and optionally at least one optical retardation layer. The invention further relates to the use of these multilayer reflective films and pigments in optical elements, as coatings or in lacquers, inks or paints for cosmetic, decorative or security applications, to inks and paints comprising one or more multilayer reflective pigments dispersed in a light transmissive binder, and to security markings or devices comprising one or more multilayer reflective films or pigments.