A forgery prevention structure, in one configuration, includes a relief forming layer, a first reflection layer, a functional thin film layer, a second reflection layer and a protection layer in this order. In this configuration, the relief forming layer has a relief structure comprising a first relief and a second relief; each of the reliefs has an uneven surface, a surface area of the uneven surface of the first relief being smaller than a surface area of the uneven surface of the second relief; the first reflection layer and the functional thin film layer each are provided along a whole of the uneven surfaces of the reliefs and each has uneven surfaces corresponding respectively to the uneven surfaces of the reliefs; and the second reflection layer and the protection layer each has an uneven surface corresponding to the uneven surface of the first relief.

The invention relates to an optical security device with multiple hidden images which become visible by arranging a polarizer above or below the device. Additional images become visible upon rotation of the polarizer. The optical device comprises two patterned optical retarders and a polarizer between the retarders.

An anti-counterfeit medium, a method for manufacturing the same and a method for preventing counterfeiting are provided. The anti-counterfeit medium includes a retardation layer having birefringence and a reflection layer, and identification data is recorded in the anti-counterfeit medium. The identification data is divided into a plurality of partial images, and a plurality of transparent areas which correspond to the plurality of partial images are disposed adjacent to each other in the same plane so as to form the retardation layer, the plurality of transparent areas having optical axes which are oriented in different directions from each other in a rotation direction. The identification data includes biometric information.

An anti-counterfeit medium, a method for manufacturing the same and a method for preventing counterfeiting are provided. The anti-counterfeit medium includes a retardation layer having birefringence and a reflection layer, and identification data is recorded in the anti-counterfeit medium. The identification data is divided into a plurality of partial images, and a plurality of transparent areas which correspond to the plurality of partial images are disposed adjacent to each other in the same plane so as to form the retardation layer, the plurality of transparent areas having optical axes which are oriented in different directions from each other in a rotation direction. The identification data includes biometric information.

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 present invention relates to a production method and to a device for document security applications including various latent images on each side. The invention comprises: depositing, according to an established pattern, at least one layer of metallized material, forming a holographic element on at least one part of one of the surfaces of a confinement substrate; defining different regions on the surface of the substrate; inducing different alignment directions for orienting a liquid crystal according to the previously defined regions; doping the liquid crystal with at least one dichroic dye; placing the liquid crystal over at least one confinement substrate, covering the holographic element; adding a second confinement substrate, forming a sandwich-type structure; and polymerizing the liquid crystal, forming a sheet.

The present invention relates to a production method and to a device for document security applications including various latent images on each side. The invention comprises: depositing, according to an established pattern, at least one layer of metallized material, forming a holographic element on at least one part of one of the surfaces of a confinement substrate; defining different regions on the surface of the substrate; inducing different alignment directions for orienting a liquid crystal according to the previously defined regions; doping the liquid crystal with at least one dichroic dye; placing the liquid crystal over at least one confinement substrate, covering the holographic element; adding a second confinement substrate, forming a sandwich-type structure; and polymerizing the liquid crystal, forming a sheet.

The invention relates to a security element (1), a security document (2) with at least one security element (1), a transfer foil (3) with at least one security element (1) as well as a method for producing a security element (1), wherein the security element has at least one layer (11) that is electrically alterable in its optical effect. It is here provided that the at least one layer (11) that is electrically alterable in its optical effect has liquid crystals (12) that can be oriented in an electric field, wherein the at least one layer (11) that is electrically alterable in its optical effect has rod-shaped dye molecules (13), and the orientations of the longitudinal axes (14) of the rod-shaped dye molecules (13) are alterable depending on the orientations of the longitudinal axes (16) of the spatially adjacent liquid crystals (12) that can be oriented in the electric field, and/or wherein the liquid crystals (12) that can be oriented in the electric field are formed in such a way that the liquid crystals (12) that can be oriented in the electric field simultaneously act as dye molecules.

The invention relates to a security element (1), a security document (2) with at least one security element (1), a transfer foil (3) with at least one security element (1) as well as a method for producing a security element (1), wherein the security element has at least one layer (11) that is electrically alterable in its optical effect. It is here provided that the at least one layer (11) that is electrically alterable in its optical effect has liquid crystals (12) that can be oriented in an electric field, wherein the at least one layer (11) that is electrically alterable in its optical effect has rod-shaped dye molecules (13), and the orientations of the longitudinal axes (14) of the rod-shaped dye molecules (13) are alterable depending on the orientations of the longitudinal axes (16) of the spatially adjacent liquid crystals (12) that can be oriented in the electric field, and/or wherein the liquid crystals (12) that can be oriented in the electric field are formed in such a way that the liquid crystals (12) that can be oriented in the electric field simultaneously act as dye molecules.

A reflective film includes a first optical stack that provides a first reflective characteristic and a second optical stack that provides a second reflective characteristic. The optical stacks also have first and second absorptive characteristics that are suitable to absorptively heat the respective stacks upon exposure to light including a write wavelength while maintaining the structural integrity of the stacks. The absorptive heating can change the first and second reflective characteristics to third and fourth reflective characteristics, respectively. A blocking layer that at least partially blocks light of the write wavelength may also be provided between the optical stacks to permit absorptive heating of any selected one of the optical stacks. The reflective characteristics of the optical stacks can thus be independently modified in any desired patterns by appropriate delivery of light beams that include the write wavelength.