The present invention can provide light-colored magnetic particles having a zirconium oxide coating layer formed on a magnetic core, and having a silver coating layer formed on the zirconium oxide coating layer, and a part of the surface of the zirconium oxide coating layer is exposed to the outside, but chemical resistance is excellent, and thus the magnetic particles hardly cause a change of magnetic characteristics so as to be suitable for security elements.

The present invention can provide light-colored magnetic particles having a zirconium oxide coating layer formed on a magnetic core, and having a silver coating layer formed on the zirconium oxide coating layer, and a part of the surface of the zirconium oxide coating layer is exposed to the outside, but chemical resistance is excellent, and thus the magnetic particles hardly cause a change of magnetic characteristics so as to be suitable for security elements.

A photonic crystal film, a method for manufacturing the photonic crystal film, and an anti-forgery article comprising the photonic crystal film are disclosed. The photonic crystal film includes a polyurethane-based polymer matrix and colloidal particles dispersed in the polyurethane-based polymer matrix and arranged in a crystal lattice structure. The colloidal particles includes one or more selected from metal nanoparticles, metal oxide nanoparticles, organic nanoparticles, and carbon structure nanoparticles.

A photonic crystal film, a method for manufacturing the photonic crystal film, and an anti-forgery article comprising the photonic crystal film are disclosed. The photonic crystal film includes a polyurethane-based polymer matrix and colloidal particles dispersed in the polyurethane-based polymer matrix and arranged in a crystal lattice structure. The colloidal particles includes one or more selected from metal nanoparticles, metal oxide nanoparticles, organic nanoparticles, and carbon structure nanoparticles.

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 of inspecting a substantially transparent light control layer for an optically variable security device and a corresponding inspection apparatus, the substantially transparent light control layer including a surface relief defined by an array of substantially transparent refractive microstructures. The method includes: directing a beam of substantially collimated light towards a first region that is expected to contain the surface relief of the light control layer so as to generate an inspection light pattern; providing reference data that is indicative of a light control layer that meets a predetermined quality threshold; comparing the inspection light pattern with the reference data; and determining whether the light control layer meets the predetermined quality threshold based on the comparison.

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 platelet-shaped magnetic effect pigment is provided for use in a printing ink, and includes a layer construction with a magnetic layer and at least one optical functional layer, such that the magnetic layer is based on a magnetic material having a column-shaped nanostructure and the magnetic columns respectively have a largely uniform preferential magnetic direction deviating from the platelet plane.

A micro-optic device, including: a substrate; a plurality of image elements; and a plurality of focusing elements, each focusing element focuses light towards, or causes light to be diverged from or constructively interfere at a real or imaginary focal point, the focusing elements causing the image elements to be sampled so as to project imagery which is observable to a user from at least a first viewing angle, wherein a first focusing structure including at least a first group of the focusing elements and a first imagery structure including at least a first group of the image elements are integrated into a first unitary structure on a first side of the substrate.