A method of forming a security device includes selectively providing a high refractive index (HRI) layer to a first outwardly facing surface of a security device substrate, the HRI layer having a substantially transparent host material and particles having a dimension along at least one axis less than 200 nm, such that they are substantially non-scattering to visible light and the HRI layer is substantially transparent to visible light, and wherein; the particles have a refractive index of at least 1.8 and are present within the host material in a proportion such that the resultant refractive index of the HRI layer is at least 1.6. A corresponding security device, as well as security articles and security documents, are also disclosed.

A document, product, or package, such as a banknote, passport or the like comprises structures having dichroic effects that change color with viewing angle in both transmission and reflection. Such structures can be useful as security features that counter the ability to effectively use counterfeit documents, products, packages, etc.

A document, product, or package, such as a banknote, passport or the like comprises structures having dichroic effects that change color with viewing angle in both transmission and reflection. Such structures can be useful as security features that counter the ability to effectively use counterfeit documents, products, packages, etc.

An optical security device (1) comprising a recorded or encoded representation of an optically variable image (40), the image (40) being reconstructable and viewable for security, authentication or identification purposes, the device (1) comprising: an optical structure (30) in which there is recorded or encoded a representation of the optically variable image (40) in the form of a plurality of discrete portions (e.g. 50) of the complete image (40) to be reconstructed, wherein the respective said plurality of portions (e.g. 50) of the optically variable image (40) can, when reconstructed, only be viewed in their totality by viewing the said image (40) at or over a plurality of different viewing angles or angle ranges (70) relative to the optical structure (30) and/or at or over a plurality of different angles or range of angles of illumination of the optical structure (10), and wherein the size, in at least one dimension, direction, axis or plane, of the complete image (40), when reconstructed, is greater than the corresponding size, in the same, or the respective same, dimension, direction, axis or plane, of a part of the optical structure (30) having the said plurality of portions (e.g. 50) of the image (40) collectively recorded or encoded therein.

A process includes providing a first layer, which is made of a non-opaque plastic material having an initial thickness, covering an area of the first layer with a patterned plate, pressing the patterned plate against a first surface of the first layer so as to form first and second regions thereon, with the second region being thicker than the first region, and removing the patterned plate from the first surface. The patterned plate comprises a cavity having a size of that corresponds to a window.

A process includes providing a first layer, which is made of a non-opaque plastic material having an initial thickness, covering an area of the first layer with a patterned plate, pressing the patterned plate against a first surface of the first layer so as to form first and second regions thereon, with the second region being thicker than the first region, and removing the patterned plate from the first surface. The patterned plate comprises a cavity having a size of that corresponds to a window.

In order to increase the security of value or security documents 100, a multi-luminescent security element 400 is provided which contains at least one first luminescence means 510 and at least one second luminescence means 520. The first luminescence means 510 can be excited under first excitation conditions Sp-1 for the purpose of luminescence, and the second luminescence means 520 can be excited under second excitation conditions Sp-2 for the purpose of luminescence, said second excitation conditions Sp-2 differing from the first excitation conditions Sp-1. The multi-luminescent security element 400 is additionally equipped with at least one absorber means 600 which prevents an excitation of the at least one first luminescence means 510 under the second excitation conditions Sp-2 for the purpose of luminescence.

In order to increase the security of value or security documents 100, a multi-luminescent security element 400 is provided which contains at least one first luminescence means 510 and at least one second luminescence means 520. The first luminescence means 510 can be excited under first excitation conditions Sp-1 for the purpose of luminescence, and the second luminescence means 520 can be excited under second excitation conditions Sp-2 for the purpose of luminescence, said second excitation conditions Sp-2 differing from the first excitation conditions Sp-1. The multi-luminescent security element 400 is additionally equipped with at least one absorber means 600 which prevents an excitation of the at least one first luminescence means 510 under the second excitation conditions Sp-2 for the purpose of luminescence.

A security element has machine-readable magnetic security features in the form of at least two magnetic materials which have different magnitudes of coercive force and which are provided as a mixture in at least one printing ink that is applied onto a carrier substrate, wherein the at least one printing ink is provided in at least two regions on the security element with the same thickness and/or different thicknesses, and a defined mixture ratio of the at least two magnetic materials with different magnitudes of coercive force is provided in the at least one printing ink.

A security element has machine-readable magnetic security features in the form of at least two magnetic materials which have different magnitudes of coercive force and which are provided as a mixture in at least one printing ink that is applied onto a carrier substrate, wherein the at least one printing ink is provided in at least two regions on the security element with the same thickness and/or different thicknesses, and a defined mixture ratio of the at least two magnetic materials with different magnitudes of coercive force is provided in the at least one printing ink.