Abstract: The invention concerns an optical security element and a system for visualising items of concealed information comprising such an optical security element. The optical security element has a substrate layer in which a relief structure defined by relief parameters, in particular relief shape, relief depth, spatial frequency and azimuth angle, is shaped in the surface region defined by an X-axis and a Y-axis, for producing an optically perceptible effect. One or more of the relief parameters defining the relief structure are varied in the surface region in accordance with a parameter variation function. The surface region is divided into one or more pattern regions and a background region. One or more of the relief parameters defining the relief structure are varied in the one or more pattern regions in accordance with a parameter variation function which is phase-displaced in relation to the parameter variation function of the background region.

Abstract: A security element which is difficult to copy includes a layer composite which has microscopically fine, optically effective structures of a surface pattern, which are embedded between two layers of the layer composite. In a plane of the surface pattern, which is defined by co-ordinate axes x and y, the optically effective structures are shaped into an interface between the layers in surface portions of a holographically non-copyable security feature. In at least one surface portion the optically effective structure (9) is a diffraction structure formed by additive superimposition of a macroscopic superimposition function (M) with a microscopically fine relief profile (R). Both the relief profile (R), the superimposition function (M) and also the diffraction structure are functions of the co-ordinates x and y. The relief profile (R) is a light-diffractive or light-scattering optically effective structure and, following the superimposition function (M), retains the predetermined profile height.

Abstract: The invention concerns an optical security element having a substrate layer, in which a first microstructure for producing a first optically perceptible effect is shaped region-wise in a surface region. The surface region is divided into microscopically fine pattern regions and a background region. The first microstructure is shaped in the pattern regions but not in the background region. The microscopically fine pattern regions in the surface region are arranged in the form of a moire pattern into which a concealed item of information which can be evaluated by means of an associated verification element is encoded as a security feature. The microscopically fine pattern regions are further substructured in accordance with a substructuring function which describes a microscopic substructuring, serving as a further security feature, of the moire pattern.

Abstract: The present invention relates to an optically variable element having surface portions with achromatic surface structures and different scatter, diffraction and reflection characteristics. The achromatic surface structures are combined with a thin-film structure, whereby upon turning or tilting the optically variable element, it is not the impression of a continuous color transition, but a defined, almost discrete color change that is produced for the viewer.

Abstract: A security element (2) in the form of a laminate can be used for the authentication of a document (1). The laminate has at least a transparent protective layer, a transparent lacquer layer and an adhesive layer, the lacquer layer being arranged between the protective layer and the adhesive layer. An interface in the form of a reflection layer separates the adhesive layer and the lacquer layer. The interface is divided into regions of a pattern (25) with flat surface portions and with relief structures which are formed in the lacquer layer. The flat surface portions form background surfaces (3) providing flat mirror surfaces for light which is incident into the laminate, while the regions with the relief structures of a predetermined, optically effective structure depth form pattern elements (4). The relief structures of the pattern elements (4) absorb the incident light.

Abstract: A diffractive security element (2) is divided into surface portions, having an optically effective structure (9) at interfaces embedded between two layers of a layer composite (1) of plastic material. At least the base layer (4), which is to be illuminated, of the layer composite (1) is transparent. The optically effective structure (9) as a base structure has a zero order diffraction grating with a period length of at most 500 nm. In at least one of the surface portions an integrated optical waveguide (5) with a layer thickness (s) of a transparent dielectric is embedded between the base layer (4) and an adhesive layer (7) of the layer composite (1) and/or a protective layer (6) of the layer composite (1), wherein the profile depth of the optically effective structure (9) is in a predetermined relationship with the layer thickness (s).

Abstract: A decorative foil is in the form of a layer composite structure (1) and comprises at least a transparent base foil (2), a transparent cover layer (4) and a transparent dielectric layer (3) arranged between the base foil (2) and the cover layer (4). When the decorative foil serves as a lamination foil for a substrate (5) the material of the cover layer (4) is an adhesive. A reflective metallic layer (6) is arranged at least in surface portions between the dielectric layer (3) and the cover layer (4) and optionally a metal film (11) is also arranged on the side of the dielectric layer (3) facing the base foil (2). General items of information shown by the decorative foil are produced by means of modulation of the thickness (s) of the dielectric layer (3). Transparent locations (7) form individual items of information, wherein the transparent locations (7) are produced with a laser beam (19) by perforating the metal layer (6; 11).

Abstract: An optically variable surface pattern (1) contains relief structures (9.1; 9.2; 9.3) for producing at least two representations (2; 3; 4). The relief structures (9.1; 9.2; 9.3) have a period length (L) of at least five micrometers and are sawtooth-shaped. The relief structures (9.1; 9.2; 9.3) associated with different representations (2; 3; 4) have different angles of inclination (?;?;?). The angles of inclination are so selected that the representations (2; 3; 4) can be perceived separately by a viewer on the one hand and on the other hand when producing a copy by means of a color photocopier they are all transferred onto the copy.

Abstract: A label (1) made from a layer composite (15) includes at least one machine-readable diffractive bar code (3) consisting of narrow rectangular fields (4) occupied by the optically active structures and intermediate surfaces (5). The optically active structures which are covered by a reflection layer are embedded between layers of the layer composite (15). The diffractive relief structure used in the diffractive bar code (3) for the fields (4) diffracts and polarizes incident light and scatters the diffracted light into a half-space above the diffractive relief structure. A second diffractive relief structure differs at least in respect of the polarization of the polarizedly backscattered light with respect to the first diffractive relief structure. The second diffractive relief structure can be used for example for field surfaces of a second bar code in the bar code field (9) on the label (1) or for the intermediate surfaces (5).

Abstract: A security element (2) comprising a plastic laminate (1) has a surface pattern which is composed mosaic-like at least from surface elements, wherein in the surface elements a reflecting interface (8) between a shaping layer (5) and a protective layer (6) of the plastic laminate (1) forms optically effective structures (9). Light (11) which is incident on the plastic laminate (1) and which passes through a cover layer (4) of the plastic laminate (1) and through the shaping layer (5) is deflected in a predetermined manner by means of the optically effective structures (9). Shaped in the surface of at least one of the surface elements is a diffraction structure which is produced by a superimposition of a linear asymmetrical diffraction grating (24) with a matt structure. The linear asymmetrical diffraction grating (24) has a spatial frequency from the range of values of between 50 lines/mm and 2,000 lines/mm.

Abstract: A light-diffractive binary grating structure has a microscopic mesa structure (2) whose plateaux (5) are separated by valleys (4) of substantially rectangular cross-section, wherein the arrangement of the valleys (4) is periodically repeated. Within a period (T) of the mesa structure (2) at least N valleys (4) separate the plateaux (5), N being an integer and greater than 2. The mesa structure (2) is an additive superimposition of N phase-shifted rectangular structures which have the same period (T) of the mesa structure (2). Each of the rectangular structures has a phase shift such that the plateaux (5) of the one rectangular structure fall into the valleys (4) of the N?1 other rectangular structures. In addition the resulting mesa structure (2) has only a single valley between two plateaux (5), which is of a width greater than a seventh of the period (T).

Abstract: A coin (1) with a metal surface (2, 3) has macroscopic reliefs (5) which serve for visually specifying the value of the coin and as an authenticity feature. Microscopically fine relief structures (8) with a diffraction effect are formed directly in at least one of the surfaces (2, 3). The relief structures (8) are preferably arranged in a recessed relationship and are covered with a lacquer (9). It is also advantageous if at least a part of the relief structures (8) entails an asymmetrical profile shape and/or the grating vectors in a radial orientation. The release structures (8) may also include a machine-readable coding which is recognized by inexpensive optical reading devices for installation in coin testers. The application of the microscopic relief structure (8) to a hard material surface (2, 3) can be effected by the removal of material by means of exposure of the material surface (2, 3) with a laser beam.

Abstract: A surface pattern (18) is in the form of a visually visible mosaic comprising a number of surface portions (8; 9; 15; 16; 17) and is embedded in a laminate (1) comprising at least a transparent cover layer (2) and a protective layer (5). The surface portions (8; 9; 15; 16; 17) are transparent, scatter or reflect incident light (10) or diffract the incident light (10) at microscopic relief structures (4). The surface portions (8; 9; 15; 16; 17) are at least partially covered with a reflection layer (3). At least one of the surface portions occupied by a microscopic relief structure (4), an area (16), is a ZOM-structure (4?) with a predeterminedly slowly varying profile height h and a spatial frequency f, wherein the product of a predetermined limit wavelength ?G of the visible spectrum and the spatial frequency f is greater than or equal to one.