The invention adds a Physical Information Layer (“PIL”) to the magnetic particles within a matrix that creates an unclonable physical unclonable function “object.” The PIL assists in searching to find the combination that matches a pre-determined enrolled combination with additional information that includes a search index, which limits the range of data required to search in order to find a match in the enrolled database. The index could be a predetermined value that associates the random magnetic profile values to a list of enrolled values in a database. The additional information may include product or general information that needs to be easily communicated to a user of the PUF.

A decorative foil, a method for producing a decorative foil as well as a method for decorating a target substrate. The decorative foil, in particular laminating foil, cold stamping foil or hot stamping foil, includes a carrier film (42) and an all-over varnish layer (41), wherein the carrier film (42) has a thickness in the range of from 3.0 μm to 10.0 μm.

A decorative foil, a method for producing a decorative foil as well as a method for decorating a target substrate. The decorative foil, in particular laminating foil, cold stamping foil or hot stamping foil, includes a carrier film (42) and an all-over varnish layer (41), wherein the carrier film (42) has a thickness in the range of from 3.0 μm to 10.0 μm.

A security element for manufacturing value documents has a structure including first and second motifs which change their appearance when the security element is tilted over a tilting angle range. The structure has first micro-elements, which are arranged with a first pattern and a first motif, and second micro-elements, which are arranged with a second pattern and a second motif. The first and second patterns are nested within each other on an areal region of the security element and have different visual appearances according to the tilting of the securing element.

A method for forming an optical device and an optical device, wherein upon illumination, exhibits diffractive images dependent upon viewing angle, the device having a diffractive structure including grating regions, each region corresponding to a component of a respective diffractive image, wherein: each region of the diffractive structure includes grating elements along a first direction having a principal orientation component within the device plane that is substantially orthogonal to the first direction; wherein, the grating elements within each grating region have a constant pitch and the same orientation wherein each grating region, upon illumination, exhibits a diffractive color wherein the corresponding diffractive image is exhibited; wherein, the diffractive structure includes first and second grating regions elongated along a common first direction, the regions being adjacent along the first direction, and wherein the pitch and/or orientation of the grating elements of the first and second grating regions are different.

A method for forming an optical device and an optical device, wherein upon illumination, exhibits diffractive images dependent upon viewing angle, the device having a diffractive structure including grating regions, each region corresponding to a component of a respective diffractive image, wherein: each region of the diffractive structure includes grating elements along a first direction having a principal orientation component within the device plane that is substantially orthogonal to the first direction; wherein, the grating elements within each grating region have a constant pitch and the same orientation wherein each grating region, upon illumination, exhibits a diffractive color wherein the corresponding diffractive image is exhibited; wherein, the diffractive structure includes first and second grating regions elongated along a common first direction, the regions being adjacent along the first direction, and wherein the pitch and/or orientation of the grating elements of the first and second grating regions are different.

A security system, such as a banknote, comprises: i) a substrate, ii) a first ink, which is applied on at least a part of at least one surface of the substrate, wherein the first ink includes at least one IR luminescent dye and/or at least one IR luminescent pigment, and iii) a second non-luminescent ink, which is applied on at least a part of at least one surface of the substrate onto which the first ink is/are applied, wherein the second ink includes at least one non-luminescent IR absorbing pigment and/or a least one non-luminescent IR absorbing dye, wherein the first ink and the second ink at least partially overlap on the at least one surface of the substrate, wherein the second ink is applied in the overlapping area onto the first ink, and wherein the emission spectrum of the first ink and the absorption spectrum of the second ink at least partially overlap.

A security system, such as a banknote, comprises: i) a substrate, ii) a first ink, which is applied on at least a part of at least one surface of the substrate, wherein the first ink includes at least one IR luminescent dye and/or at least one IR luminescent pigment, and iii) a second non-luminescent ink, which is applied on at least a part of at least one surface of the substrate onto which the first ink is/are applied, wherein the second ink includes at least one non-luminescent IR absorbing pigment and/or a least one non-luminescent IR absorbing dye, wherein the first ink and the second ink at least partially overlap on the at least one surface of the substrate, wherein the second ink is applied in the overlapping area onto the first ink, and wherein the emission spectrum of the first ink and the absorption spectrum of the second ink at least partially overlap.

The present invention relates to metal oxide nanoparticles, a method for their production, a coating, or printing composition, comprising the metal oxide nanoparticles and the use of the composition for coating of surface relief micro- and nanostructures (e.g. holograms), manufacturing of optical waveguides, solar panels, light outcoupling layers for display and lighting devices and anti-reflection coatings. Holograms are bright and visible from any angle, when coated, or printed with the composition, comprising the metal oxide nanoparticles.

The present invention relates to metal oxide nanoparticles, a method for their production, a coating, or printing composition, comprising the metal oxide nanoparticles and the use of the composition for coating of surface relief micro- and nanostructures (e.g. holograms), manufacturing of optical waveguides, solar panels, light outcoupling layers for display and lighting devices and anti-reflection coatings. Holograms are bright and visible from any angle, when coated, or printed with the composition, comprising the metal oxide nanoparticles.