VACCUM ROLL COATED SECURITY THIN FILM INTERFERENCE PRODUCTS WITH OVERT AND/OR COVERT PATTERNED LAYERS HAVING FABRY-PEROT STRUCTURE OR SPACED PARRALLEL FILTERS

摘要

PURPOSE: Provided is a security thread to provide protection against forgery, which is embedded in sheets such as bank notes or documents and has thin film interference structure deposited thereon such as Fabry-Perot structure or spaced parallel filters. CONSTITUTION: The security thread comprises an elongate substrate(20) and optical variable structures(21) on one side of the elongate substrate. The optical variable structures are arranged in parallel and comprise visible patterns having visible color shifting property such that they are identified visually. The patterns are prepared by the steps of coating the substrate with the first material, applying the layer of the second material on the first material or the portion of substrate on which the first material is not coated, removing the first material and the layer of the second material on the first material and leaving the second material on the portion where the substrate is not coated by the first material, and coating the third and the fourth layer on the second material and forming Fabry-Perot filters in separate areas.