Security document with integrated security device and method of manufacture

摘要

A security document (1) is provided having a substrate (4) and an integral security device (10) which includes an image layer (12) and a focussing layer (11). each formed from a radiation curable ink layer embossed with relief formations (13; 15). The first radiation curable layer embossed with relief formations (13) to form the image layer (12) is provided on a first surface of the document, and the second radiation curable layer (11) embossed with focussing element relief formations (15) is provided on a second surface of the document. The first and second surfaces are separated by a predetermined distance D to produce a visible optical effect when viewing the image layer (12) through the focussing layer (11). In preferred embodiments, at least one of the first and second radiation curable layers is embossed with diffractive relief structures and high refractive index or reflective coatings may be applied to the embossed relief formations in the image layer (12) and/or the focussing layer (11). The invention allows security devices to be integrated in a security document, such as a banknote, in a cost-effective manner, without substantially increasing the thickness of the document.