Abstract:
Die Erfindung betrifft ein Verfahren zum Herstellen eines Hologramms, insbesondere eines Transmissionshologramms, umfassend: Bereitstellen von einem Aufzeichnungshologramm (703, 803, 1203), Belichten des Aufzeichnungshologramms (703, 803, 1203) mit einem durch eine kohärente Lichtquelle (809) erzeugten Objektstrahl (704, 804, 1204), wobei ein abzubildendes Objekt (711, 811,1231) in dem Objektstrahlengang vorgesehen ist, und Belichten des Aufzeichnungshologramms (703, 803, 1203) mit einem durch die kohärente Lichtquelle (809) erzeugten Referenzstrahl (705, 805, 1205), wobei der Referenzstrahl (705, 805, 1205) von einem optischen Referenzmodul (716, 816, 1230) derart winkelgeändert wird, dass der Referenzstrahl (705, 805, 1205) am Ort des Aufzeichnungshologramms (703, 803, 1203) ein Winkelspektrum aufweist.
Abstract:
The present invention relates to a security element (1; 30) intended for being added to or on a security document (21; 31), including at least one first optical structure (2) such as a standard rainbow hologram and/or a raster image representing a first pattern (22) and at least one second optical structure (3), which is achromatic and represents a second pattern (23) at least partially identical to the first pattern (21).
Abstract:
The invention, provides a computer-generated hologram which can be viewed in white at the desired viewing region and a reflective liquid crystal display using the same as a reflector. The computer-generated hologram H is designed to diffuse light having a given reference wavelength λ STD and incident thereon at a given angle of incidence θ in a specific angle range. In a range of wavelengths λ MIN to λ MAX including the reference wavelength λ STD wherein zero-order transmission light or zero-order reflection light of incident light on the computer-generated hologram at a given angle of incidence is seen in white by additive color mixing, the maximum diffraction angle β 2MIN of incident light of the minimum wavelength λ MIN in the wavelength range and incident at the angle of incidence θ is larger than the minimum diffraction angle β 1MAX of incident light of the maximum wavelength λ MAX in the wavelength range and incident at said angle of incidence θ.
Abstract:
The invention provides a computer-generated hologram which can be viewed in white at the desired viewing region and a reflective liquid crystal display using the same as a reflector. The computer-generated hologram H is designed to diffuse light having a given reference wavelength λ STD and incident thereon at a given angle of incidence θ in a specific angle range. In a range of wavelengths λ MIN to λ MAX including the reference wavelength λ STD wherein zero-order transmission light or zero-order reflection light of incident light on the computer-generated hologram at a given angle of incidence is seen in white by additive color mixing, the maximum diffraction angle β ZMIN of incident light of the minimum wavelength λ MIN in the wavelength range and incident at the angle of incidence θ is larger than the minimum diffraction angle β 1MAX of incident light of the maximum wavelength λ MAX in the wavelength range and incident at said angle of incidence θ.
Abstract:
The invention relates to a color hologram display of an image of a three-dimensional object and a hologram image of a pattern of plane characters, the images or the like are recorded in the same volume type hologram photosensitive material in a superposed or multiplexed fashion. A color hologram display (27') comprising a combined reflection and volume type of single layer, wherein a color pattern (29g) of plane characters, images or the like and a color three-dimensional subject image O'' are reconstructably recorded while spatially superposed one upon another.
Abstract:
A surface relief hologram that comprises two or more patterns, each pattern being sensitive to different radiation wavelengths. The hologram is made by defining relief features that are sensitive to different wavelengths, and in particular to one wavelength that is visible to the unaided human eye and to one wavelength that is invisible to the unaided human eye. These relief features of different sensitivities are interspersed over the surface of the substrate in which the hologram is defined. By providing two patterns of different sensitivities, when the hologram is used in a security device, security is improved. Despite this improved security, the hologram can be mass manufactured using known techniques.
Abstract:
A single method and apparatus for producing many of the most common types of hologram from digital data is disclosed. In one embodiment the data are generated entirely by a computer as a 3-D (animated) model. In another embodiment the data are generated from multiple 2-D camera images taken of a real 3-D (moving) object or scene from a plurality of different camera positions. The data are digitally processed and displayed on a small high resolution spatial light modulator (SLM). A compact low energy pulsed laser, which avoids the usual vibration problems encountered at high rates of production and the installation in normal working environments, is used to record composite holograms on an holographic emulsion using a special optical design. The present invention permits the creation of restricted or full parallax master transmission or reflection type composite holograms, known as H1 holograms, that can be copied using traditional methods to produce full or single colour rainbow white-light transmission holograms, achromatic white-light transmission holograms or single or full-colour white-light reflection holograms. Alternatively the same invention and apparatus permits the direct writing of full or single colour rainbow white-light transmission composite holograms, achromatic white-light transmission composite holograms or single or full-colour white-light reflection composite holograms without the need to pass through the intermediate stage of the H1 transmission hologram. The present invention allows the creation of a compact rugged machine that is capable of producing holograms covering a large size range. In addition the invention produces holograms that can be tiled together to form composite holograms much larger than the component panels.