Element for protection against forgery or copying containing a structured retarder and a polarizer layer

US7292292B2 · kind B2 · utility

Assignee

• Rolic Ltd c/o Rolic Technologies Ltd · CH

Inventors

• Martin Schadt · Seltisberg, CH
• Hubert Seiberle · Lörrach, DE

Key dates

• Filing date: Jun 20, 2006
• Grant date: Nov 6, 2007
• Expiry date: Jun 20, 2026

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B5/32
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A component has a substrate (1) made of a transparent material, for example glass. On this layer (1), there is a linear polarizer (2) on which there is a layer (3) of a photo-oriented polymer network (PPN)(=LPP) which is oriented in locally varying fashion via its surface which covers the substrate. The layer (3) is adjoined by an anisotropic layer (4) of cross-linked liquid-crystal monomers. This layer (4) then has a molecular arrangement whose orientation is defined by the underlying orientation layer (3). The layer (4) will have been photocross-linked by exposure to a suitable wavelength of light, with the result that the molecular orientation defined by the PPN layer (3) is fixed. The element, denoted as a whole by 7, can then be used as an optical component which is protected against forgery, it being possible for the orientation pattern of the liquid-crystal layer or the optical information stored therein to be made visible by means of an external polarizer (5), for example.