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: 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) 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 security element (2) for sticking onto a document (3) comprises a layer composite (1) of plastic material and has embedded, optically effective structures of a pattern (4). The optically effective structures in surface portions (13) of the pattern (4) are in a reference plane, defined by co-ordinate axis (x; y), of the layer composite (1) and are shaped into a reflecting interface. The interface is embedded between a transparent shaping layer and a protective layer of the layer composite (1). At least one surface portion (13) is of a dimension of greater than 0.4 mm and in the interface has at least one shaped macrostructure (M) which is an at least portion-wise steady and differentiatable function of the co-ordinates (x; y). The macrostructure (M) is curved at least in partial regions and is not a periodic triangular or rectangular function. In the surface portion (13) adjacent extreme values of the macrostructure (M) are at least 0.1 mm away from each other.

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 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 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 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: 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: 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 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 label (1) comprising 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 is embedded in a layer composite of plastic material and has reflecting, optically variable surface patterns which can be visually recognized from predetermined observation directions and which are formed from a mosaic of surface elements occupied by optically active structures. A part of the surface pattern is additionally covered by a regularly arranged matrix of unit cells. Each unit cell is occupied by a single elementary surface or a group of identical surface portions that contain optically active structures which are independent of the mosaic of the surface pattern. The arrangement of the elementary surfaces and the surface portions in the matrix form an item of concealed information which is not perceptible to the naked eye, in the form of graphic or alphanumeric characters which however are reproduced in a color photocopy with a color or gray value contrast which is perceptible to the naked eye.

Abstract: A layer composite of plastic material forms a retroreflector and includes at least one transparent structure layer, a protective layer and a reflection layer enclosed at the common interface between the structure layer and the protection layer. A relief structure formed by substantially identically shaped three-dimensional structure elements is formed in the reflection layer. At their base surfaces the structure elements are of lateral dimensions in the range of between 1 &mgr;m and 100 &mgr;m. The structure elements have side faces which are covered by the reflection layer and which include an angle of inclination of 45°, with a free surface of the layer composite. The relief structure is additively superimposed with a microstructure in at least one surface element. The microstructure has a preferred direction and influences the quality of the reflection action of the layer composite. The retroreflector is suitable for the production of machine-readable optical markings.

Abstract: A security element which is stuck on to a substrate has a reflecting, optically variable surface pattern (11) which is embedded in a layer composite of plastic material and which is visually recognisable to the naked eye from predetermined observation directions. The surface pattern (11) is formed from a mosaic of surface elements (12; 13; 14) with optically active structures. At least in a part of the surface pattern (11) identical surface portions (15) with optically active relief structures are additionally arranged regularly in regions which are independent of the mosaic. The surface portions (15) involve a largest dimension of less than 0.2 mm and a length-to-width ratio of at least 3:1, wherein the center points (16) of the surface portions form a dot matrix with periods of more than 8 dots per mm and the longitudinal surface portions (15) in each region are oriented parallel to a preferred direction.

Abstract: A security element (1) is embedded in a layer composite of plastic material and has reflecting, optically variable surface patterns (11) which can be visually recognised from predetermined observation directions and which are formed from a mosaic of surface elements (12; 13; 14) occupied by optically active structures. A part of the surface pattern (11) is additionally covered by a regularly arranged matrix (18) of unit cells (15). Each unit cell (15) is occupied by a single elementary surface (16) or a group of identical surface portions (17), wherein the elementary surfaces (16) and the surface portions (17) contain optically active structures (4) which are independent of the mosaic of the surface pattern (11).

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: In order to improve target illumination, a light source (2) of an emitter, which has a laser diode (3) configured as an edge emitter with a wavelength of 1,550 nm, has beam forming optics (4) mounted downstream in relation thereto, which comprise a cylindrical lens (7) and a first deflection element (8) with three fields having different diffraction structures. Said deflection element are located next to one another and crosswise in relation to the first fields and which also have different diffraction structures. Said deflection element directs the partial beams to the aperture of a collimator (1) in such a way that the partial beams substantially fill said aperture. The first deflection element (8) and a mount (6) for the cylindrical lens (7) are integral and, alike the second deflection element (10), are made of plastic. Both parts are glued to opposite sides of the frontal areas of a block (5) made of glass.

Abstract: A first texture mapping unit generates texture coordinates and associated Red, Blue, Green (RGB) values in response to coordinates received from a rasterizer. The first texture mapping unit makes use of compressed texture mipmaps to reduce memory storage and bandwidth requirements. The compressed texture maps may be generated by a compression system employing principles of Block Truncation Coding (BTC) and Color Cell Compression (CCC). A second texture mapping unit generates texture coordinates and associated RGB values in response to coordinates received from a rasterizer. The second texture mapping unit includes a memory organization allowing two mipmap levels to be retrieved in a single access, and 8-port Color Lookup Table (CLUT), a trilinear interpolator and a video port. A footprint assembly system maps textures onto surfaces by approximating the projection of a pixel onto a texture by a number of square mipmapped texels.