A security device formed by a hologram and a color shifting ink

Abstract

A method of forming a label on an object (24) is provided, comprising the steps of coating a surface of the object (64) with optically variable ink, and bonding a patterned structure to the object (24) with a light transmissive adhesive over the optically variable ink. The patterned structure allows light to propagate therethrough, and may be a diffractive structure comprising one of: a semi transparent reflective layer, a high refraction index layer, and a patterned reflective coating. In one embodiment a hologram is hot stamped to a banknote or paper document printed with a color-shifting ink.

Description

technical field

[0001] The present invention relates to forming a label on the surface of an item by printing an optically variable ink on the item and adhesively bonding a patterned structure, such as a hologram, to the optically variable ink by, for example, thermal embossing. Background technique

[0002] Security labels, also known as optical security devices, are used to protect various items from counterfeiting. These items include paper documents, banknotes, merchandise, packaging, etc. Typically, security labels are adhesively bonded or heat embossed on the surface of an article or package.

[0003] A type of security label that is an optical structure that exhibits the effect of an embossed or etched surface relief pattern, such as a hologram or diffraction grating, and patterns having, for example, alphanumeric features, bar codes, or pictorial or pictorial designs , and other optical effects in the area surrounding this pattern. This structure is described in U...

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