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Proceedings Paper

Optical LPP/LCP devices: a new generation of optical security elements
Author(s): Franco Moia; Hubert Seiberle; Martin Schadt
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Paper Abstract

With linear photo polymerization (LPP) ROLIC has developed a new photo-patternable technology which enables to align not only conventional liquid crystals bu also LCP. ROLICs optical security device technology derives from its LPP/LCP technology. LPP/LCP security devices are crated by structured photo-alignment of an LPP layer through photo- masks, thus generating a high resolution, photo-patterned aligning layer which carries the aligning information of the image to be created and which is machine readable. The subsequent LCP layer transforms the aligning information into an optical phase image. Among a large number of possible LPP/LCP optical effects that lead to LPP/LCP security devices - all of them with distinct optical appearance - we will concentrate on the following LPP/LCP security elements: Reflective and transmissive LPP/LCP security devices for 2nd level inspection applications. LPP/LCP images are invisible when viewed with the naked eye but becomes visible when viewed through a polarizer. Rotation of the polarizer leads to contrast inversion: i.e. the image changes from 'positive' to 'negative' which is an additional unique security feature. Other types of LPP/LCP security devices are based on cholesteric films. We will present 2nd level cholesteric LPP/LCP devices which can be sued as overlays and superimposed on printed information which remains visible through the overlay.

Paper Details

Date Published: 7 April 2000
PDF: 8 pages
Proc. SPIE 3973, Optical Security and Counterfeit Deterrence Techniques III, (7 April 2000); doi: 10.1117/12.382188
Show Author Affiliations
Franco Moia, Rolic Research Ltd. (Switzerland)
Hubert Seiberle, Rolic Research Ltd. (Switzerland)
Martin Schadt, Rolic Research Ltd. (Switzerland)

Published in SPIE Proceedings Vol. 3973:
Optical Security and Counterfeit Deterrence Techniques III
Rudolf L. van Renesse; Willem A. Vliegenthart, Editor(s)

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