According to one aspect, the invention relates to an optical safety component having a plasmonic effect intended to be observed by transmission, including two layers (101, 103) made of a transparent dielectric material, a metal layer (102) that is arranged between said layers made of dielectric material to form two dielectric-metal interfaces (105, 106), and is structured to form on at least a portion thereof corrugations (104) that are capable of coupling surface plasmon modes supported by said dielectric-metal interfaces with an incident light wave. The corrugations are arranged in a first coupling area in a first main direction and in at least one second coupling area separate from said first coupling area, in a second main direction that is substantially perpendicular to said first main direction, said metal layer being continuous on each one of said coupling areas.

Security documents often incorporate optically variable devices to prevent or hinder counterfeiters. Disclosed herein are layered optically variable devices such as color-shift foils, and methods for their production and use. Such devices afford new techniques for a user of a security document to check quickly and easily whether the security document is a legitimate document or a counterfeit copy.

An optically variable surface pattern is made available, having at least two partial areas with reflection elements, wherein the reflection elements of the first partial region on the one hand and the reflection elements of the second partial region on the other hand reflect impinging light in different reflection directions. The first partial region is so covered with a first glazing ink layer that a viewer, upon a change of the viewing angle at which the viewer views the optically variable surface pattern, sees the first partial region glow in a first color upon reaching a first viewing angle. The second partial region glows in a second color that is different from the first color upon reaching a second viewing angle.

The present disclosure relates to a security structure including a non-opaque, preferably transparent, substrate. The substrate supports metal elements forming a revealing pattern. The metal is thin enough for the metal to be non-opaque. A lacquer is placed at least partially, preferably exactly, on top of the metal elements. The lacquer may be in contact with the metal elements.

A security device is provided including a first pattern of elements and a second, overlapping, pattern of elements spaced by a transparent layer, the first and second patterns in combination obstructing the passage of light transmitted to a viewer through the device to a varying degree depending on the viewing position. The first and second patterns of elements are configured such that a first region of the device exhibits a maximum change in the degree of obstruction when the device is tilted relative to the viewer about a first tilt axis, and a second region of the device exhibits a maximum change in the degree of obstruction when the device is tilted relative to the viewer about a second tilt axis which is not parallel to the first tilt axis.

The invention concerns a security element for a security document comprising a structure layer and diffractive first and second relief structures, wherein the relief structures viewed parallel to the plane of the structure layer are arranged in different planes of the security element, wherein the first relief structure adjoins a partial first reflection layer and the second relief structure adjoins a partial second reflection layer, and whereinif the first reflection layer is towards a viewera second item of information generated by the second relief structure is at least partially concealed andif the second reflection layer is towards the viewera first item of information generated by the first relief structure is at least partially concealed, and processes for the production of such security elements and security documents formed therewith.

A security device for verifying an authenticity of a security document comprises an at least partially transparent substrate with a first surface and a second surface. A first pattern is arranged on the first surface. A second pattern is arranged on said second surface. The first and the second pattern each comprise a plurality of pixels with at least three different gray levels visible from a macroscopic perspective. The first and second pattern cover only gray levels in a range between 20% black and 80% black, in particular between 35% black and 65% black. The first pattern is inverted with respect to the second pattern.

The invention relates to a security element (1) with authentication information (2) for checking the correct combination of two support parts (3, 4, 5), characterized in that the security element (1) comprises at least one first partial element (6) comprising first partial information (7) and a second partial element (8) comprising second partial information (9). The first partial element (6) can be associated with a first support part (3) and the second partial element (8) can be associated with a second support part (4), both partial elements (6, 8) can be moved from a starting position into a checking position in which both partial elements (6, 8) overlap. The first partial information (7) and the second partial information (9) represent the authentication information (2) when in the checking position.

An anti-counterfeit medium includes a portion having optical transparency, a retardation layer facing the portion and including regions whose slow axis directions are different from each other, and a polarizing layer facing the retardation layer at a position of the portion. The anti-counterfeit medium includes only the polarizing layer as a polarizer. A portion out of the anti-counterfeit medium where the portion, the retardation layer, and the polarizing layer form a stacked structure has optical transparency.

The invention relates to a security element (2) with a first area (30) that is transparent in transmitted light. The security element (2) has a substrate (21) which has, in the first area (30), one or more transmissive diffraction structures which display one or more optical security features when observed in transmitted light.