An object of the present invention is to provide a thin volume hologram sheet to be embedded sufficiently resistant to a mechanical stress such as a stress including a tensile stress, a shear stress and a compression stress at the time of processing even under a heating condition, a forgery prevention paper and a card using the same. The object is achieved by providing a volume hologram sheet to be embedded comprising a volume hologram layer, and a substrate disposed only on one side surface of the volume hologram layer using an adhesion means, wherein a peeling strength of the volume hologram layer and the substrate is 25 gf/25 mm or more.

A method of manufacturing a security device including: conveying a substrate web including a photosensitive film along a transport path; exposing the photosensitive film to radiation of a predetermined wavelength through a mask, wherein the mask includes a predetermined pattern of regions which are substantially opaque to radiation of the predetermined wavelength and at least semi-transparent to radiation of the predetermined wavelength, respectively; during the exposure, moving the mask alongside the substrate web along at least a portion of the transport path at substantially the same speed as the substrate web, such that there is substantially no relative movement between the mask and the substrate web; and heating the substrate web including the exposed photosensitive film. In this way, regions of the photosensitive film exposed to the radiation of the predetermined wavelength undergo an increase in optical density such that the photosensitive film displays a reproduction of the predetermined pattern.

An optically variable areal pattern has a reflection layer and a micromirror arrangement comprising a plurality of semitransparent micromirrors developed on the reflection layer. The micromirrors are inclined with respect to the reflection layer, such that, by specular reflection, light incident on the micromirror arrangement is reflected on the semitransparent micromirrors. The incident light is reflected partly in a first direction and partly in a second direction that is different from the first direction, in that it passes through the semitransparent micromirrors, impinges on the reflection layer, and is reflected there and, thereafter, again passes through the semitransparent micromirrors.

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 invention relates to the use of nanosystems as non deactivable security markers comprising metal atomic quantum clusters (AQCs) of at least two different size distributions encapsulated in a cavity with an inner diameter less than or equal to approximately 10 nm. These nanosystems are luminescence, particularly fluorescence after external excitation. The invention also relates to security documents, articles or elements incorporating these markers as well as to a method and a system for detecting the same.

An object of the present invention is to provide a thin volume hologram sheet to be embedded sufficiently resistant to a mechanical stress such as a stress including a tensile stress, a shear stress and a compression stress at the time of processing even under a heating condition, a forgery prevention paper and a card using the same. The object is achieved by providing a volume hologram sheet to be embedded comprising a volume hologram layer, and a substrate disposed only on one side surface of the volume hologram layer using an adhesion means, wherein a peeling strength of the volume hologram layer and the substrate is 25 gf/25 mm or more.

An object of the present invention is to provide a thin volume hologram sheet to be embedded sufficiently resistant to a mechanical stress such as a stress including a tensile stress, a shear stress and a compression stress at the time of processing even under a heating condition, a forgery prevention paper and a card using the same. The object is achieved by providing a volume hologram sheet to be embedded comprising a volume hologram layer, and a substrate disposed only on one side surface of the volume hologram layer using an adhesion means, wherein a peeling strength of the volume hologram layer and the substrate is 25 gf/25 mm or more.

A multilayer body includes a transparent first layer. In the transparent first layer, a multiplicity of microlenses arranged in accordance with a microlens grid are impressed in a first region. Furthermore, the multilayer body includes a second layer, which is arranged below the first layer and in a fixed position with respect to the first layer and has a multiplicity of microimages arranged in accordance with a microimage grid and in each case in an at least regional overlap with one of the microlenses of the microlens grid for the purpose of generating a first optically variable information item. The grid pitches of the microimage grid and of the microlens grid in each case in at least one spatial direction are less than 300 μm.

Disclosed herein is a method for forming a surface relief microstructure, including the steps of A) applying a curable composition to at least a portion of the frontside of the paper substrate, B) contacting at least a portion of the curable composition with surface relief microstructure, C) curing the composition by using at least one UV lamp which is arranged on the backside of the paper substrate, and D) depositing a metallic layer, and optionally a layer of a transparent high refractive index material, on at least a portion of the cured composition, wherein the UV lamp has an emission peak in a UV-A range of 320 nm to 400 nm and additionally in a near VIS range of 400 nm to 450 nm, the curable composition comprises a photoinitiator which absorbs in the UV-A range and also in the near VIS range.