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Proceedings Paper

Optically variable devices for use on bank notes
Author(s): John Rolfe
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Paper Abstract

The security of bank notes against counterfeiting can be improved by the incorporation of optically variable devices (OVDs), which change their appearance when the note is viewed in different directions. Three types of OVD; holograms, multiple diffraction gratings, and thin film interference filters will be compared in relation to the special requirements unique to bank notes; security, visibility and durability. The Bank of Canada has recently issued $50 bank notes bearing a five-layer thin film interference filter. The tests which led to this particular form of OVD will be described, together with methods of deposition, quality control, and application to sheets of bank notes.

Paper Details

Date Published: 1 April 1990
PDF: 6 pages
Proc. SPIE 1210, Optical Security and Anticounterfeiting Systems, (1 April 1990); doi: 10.1117/12.17908
Show Author Affiliations
John Rolfe, Bank of Canada (Canada)

Published in SPIE Proceedings Vol. 1210:
Optical Security and Anticounterfeiting Systems
William F. Fagan, Editor(s)

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