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Proceedings Paper

Elemental analysis of kinematic optically variable devices
Author(s): Michael M. Chamberlain
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Paper Abstract

OVDs are increasingly used as a means of authenticating documents or reducing the chances of successful counterfeiting. Kinematic effects are those observed when certain image elements appear to move on rotation or tilting of the substrate. Examples of devices showing these effects are described as 'Kinegrams' or 'Exelgrams' or, more recently, 'Kineforms.' All are produced by the creation of microscopic diffracting structures. All have in common: graphical animation, well defined mutual movements, an abandonment of holographic three dimensionality, and the ability to perform under diffuse lighting conditions and under most viewing angles. The images are not based on objects but are computer generated. Their principal advantage is that they can only be produced using highly sophisticated manufacturing techniques. These techniques are radically different from each other, and it is therefore surprising that the observed effects are so similar. This paper attempts to describe the observed features of kinematic OVDs in a structured way and to assess their relative performance on a micro as well as a macro scale, using a mixture of optical and scanning electron microscopy. It is hoped that this work will contribute towards a system of classification of KOVDs which will assist prospective users in the specification of such products.

Paper Details

Date Published: 15 March 1996
PDF: 11 pages
Proc. SPIE 2659, Optical Security and Counterfeit Deterrence Techniques, (15 March 1996); doi: 10.1117/12.235459
Show Author Affiliations
Michael M. Chamberlain, Pira International (United Kingdom)


Published in SPIE Proceedings Vol. 2659:
Optical Security and Counterfeit Deterrence Techniques
Rudolf L. van Renesse, Editor(s)

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