A method for producing a volume hologram with at least one first area in a first color and at least one second area in a second color includes, providing a volume hologram layer made of a photopolymer; arranging a master with a surface structure on the volume hologram layer; exposing the master using coherent light, wherein light which is incident on at least one first partial area of the surface of the master is diffracted or reflected in the direction of the at least one first area of the volume hologram layer and light which is incident on at least one second partial area of the surface of the master is diffracted or reflected in the direction of the at least one second area of the volume hologram, and wherein the light diffracted or reflected by the first and second partial areas differs in at least one optical property.

A method for producing a volume hologram with at least one first area in a first color and at least one second area in a second color includes, providing a volume hologram layer made of a photopolymer; arranging a master with a surface structure on the volume hologram layer; exposing the master using coherent light, wherein light which is incident on at least one first partial area of the surface of the master is diffracted or reflected in the direction of the at least one first area of the volume hologram layer and light which is incident on at least one second partial area of the surface of the master is diffracted or reflected in the direction of the at least one second area of the volume hologram, and wherein the light diffracted or reflected by the first and second partial areas differs in at least one optical property.

A method for producing a hologram on a curved substrate plate includes providing a curved substrate plate having a substrate surface, the actual geometry of which is subject to a tolerance deviation with respect to a predetermined desired geometry; providing an inflatable cushion with a cushion surface that can be deformed under the effect of pressure and is preformed into the predetermined desired geometry or with a predetermined deviation therefrom; applying a holographic master in the form of a flexible thin layer to the deformable cushion surface and applying a hologram-recording layer to the substrate surface; pressing or placing the holographic master onto the hologram-recording layer by way of the cushion surface deformed to the actual geometry, thereby achieving full surface-area contact between them with a substantially constant predetermined layer thickness of the hologram-recording layer, and exposing the hologram-recording layer to form a hologram.

A holographic projector comprises an image processing engine arranged to, a hologram engine and a display engine. The image processing engine is arranged to receive a source image for projection. The source image comprises a first colour component and a second colour component. The image processing engine is further arranged to form a first colour secondary image from the first colour component by nulling alternate pixel values of the first colour component in accordance with a first checkerboard pattern. The image processing engine is further arranged to form a second colour secondary image from the second colour component by nulling alternate pixel values of the second colour component in accordance with a second checkerboard pattern. The first checkerboard pattern is opposite to the second checkerboard pattern. The hologram engine is arranged to determine a first colour hologram corresponding to the first colour secondary image and a second colour hologram corresponding to the second colour secondary image. The display engine is arranged to form a first colour holographic reconstruction from the first colour hologram and a second colour holographic reconstruction from the second colour hologram.

Various embodiments of this disclosure relate to a piecewise varying rolled K-vector grating structure including: a first grating section containing a grating with a first K-vector, a second grating section containing a grating with a second K-vector; and a first boundary region positioned between the first grating section and the second grating section. The first boundary region is a multiplexed grating region including both the first K-vector and the second K-vector. Further disclosed is a method for recording such a grating structure utilizing a holographic recording process. Providing a multiplexed grating in the first boundary region may largely remove line exposure artifacts between adjacent sections of the P-RKV grating.

A method for producing a hologram (1), (1) for security elements (1a) and/or security documents (1b). One or more virtual hologram planes (10) are arranged in front of and/or behind one or more virtual models (20) and/or one or more virtual hologram planes (10) are arranged such that they intersect one or more virtual models (20). One or more virtual light sources (30) are arranged on one or more partial regions of the surface (21) of one or more of the virtual models (20). One or more virtual electromagnetic fields (40) are calculated starting from at least one of the virtual light sources (30) in one or more zones (11) of the one or more virtual hologram planes (10). In the one or more zones (11), in each case, a virtual total electromagnetic field (41) is calculated on the basis of the sum of two or more, of the virtual electromagnetic fields (40) in the respective zone (11). One or more phase images (50) are calculated from the virtual total electromagnetic fields (41) in the one or more zones (11). A height profile (60) of the hologram (1) is calculated from the one or more phase images (50) and the height profile (60) of the hologram (1) is incorporated into a substrate (2) to provide the hologram (1).

A method for producing holograms with a multiplicity of holographic prescriptions from a single master is provided. A multiplicity of holographic substrates each containing a first hologram is stacked on a second holographic recording medium substrate. The first hologram is designed to diffract light from a first direction into a second direction. When expose to illumination from the first direction zero order and diffracted light from each first hologram interfere in the second holographic recording medium substrate forming a second hologram. The second hologram is then copied into a third holographic recording medium substrate to provide the final copy hologram.

A lighting device for a vehicle, in particular a headlamp for a vehicle, having at least one light source, from which light emanates during the operation of the lighting device, a diffractive optical unit, including a plurality of gratings, which form a grating cell array, the light passing through the grating cell array during the operation of the lighting device in such a way that a light distribution is created in the outer area of the vehicle, at least one of the gratings of the grating cell array being designed as a volume hologram.

The layered generation of at least one volume grating in a recording medium by way of exposure, the recording medium having at least one photosensitive layer which is sensitized for a presettable wavelength of the exposure light. Each volume grating is generated in the recording medium by at least two wave fronts of coherent light capable of generating interference, the wave fronts being superposed in the recording medium at a presettable depth, at a presettable angle and with a presettable interference contrast. The depth and the thickness of the refractive index modulation and/or transparency modulation of a volume grating in the recording medium is controlled by depth-specific control of the spatial and/or temporal degree of coherence of the interfering wave fronts in the direction of light propagation.

A process is provided for producing a hologram that can be applied in particular to a curved carrier, characterized by the process steps of bending a flat, photosensitive recording material and projecting the hologram into the curved recording material.