A holographic display apparatus for providing an expanded viewing window includes a spatial filter configured to separate a plurality of holographic images generated by the hologram pattern displayed on the spatial light modulator from a plurality of lattice spots generated by a physical structure of the spatial light modulator. The spatial filter includes a plurality of color filters or a plurality of dichroic mirrors separating a first color image, a second color image, and a third color image from a first color lattice spot, a second color lattice spot, and a third color lattice spot.

Provided is a holographic display apparatus including a light source configured to emit light, a spatial light modulator configured to form a hologram pattern to modulate the light incident thereon and reproduce a hologram image, the spatial light modulator including a plurality of display pixels that are arranged two-dimensionally, and an optical element provided opposite a light incidence surface of the spatial light modulator or a light exit surface of the spatial light modulator, the optical element including an array of a plurality of light transmission patterns that are arranged irregularly.

A three-dimensional holographic display device includes a light emitting diode (LED) array including a plurality of light sources controlled to sequentially output light according to a preset pattern, a lens configured to refract light incident from the LED array, a spatial light modulator (SLM) configured to modulate light incident from the lens, and a processor configured to generate a plurality of holographic signals each comprising depth information adjusted according to an arrangement location of each of the plurality of light sources, and for each of the plurality of light sources, control the SLM to modulate the light based on a holographic signal corresponding to the light source.

The invention relates to a multilayer body with a volume hologram layer and a partial opaque layer, arranged on a surface of the volume hologram layer, which is present in a first area and is not present in a second area. The invention furthermore relates to a method for the production of such a multilayer body, as well as a security element and security document with such a multilayer body.

The invention relates to a holographic display device for representing a two-dimensional and/or three-dimensional scene. The holographic display device comprises at least one spatial light modulator device and an optical component. The at least one spatial light modulator device is provided in order to reconstruct the scene and in order to generate at least one virtual visibility region in an observer plane. The optical component is configured with at least two regions that have a different transparency to one another, the value of the transparency respectively lying between 0 and 1. Furthermore, the optical component is arranged in the display device in such a way that it provides filtering, to be carried out at least partially, of a diffraction order spot in at least one diffraction order inside the virtual visibility region.

An optical image generation system including: a spatial light modulator (SLM) configured to receive an input collimated laser beam and modulate the wavefront of the laser beam; one or more optical elements configured to project the modulated laser beam onto a focal plane; a first mirror and a second mirror situated at the focal plane, an edge of the first mirror being adjacent to an edge of the second mirror, the first mirror reflects a first portion of the modulated laser beam in a first direction, the second mirror reflects a second portion of the modulated laser beam in a second direction; and an objective lens projects the first and second portions into a combined image; wherein the zeroth order diffraction is block or suppressed at the center of the focal plane.

A totagram is produced by an iterative spectral phase recovery process resulting in complete information recovery using special masks, without a reference beam. Using these special masking systems reduce computation time, number of masks, and number of iterations. The special masking system is (1) a unity mask together with one or more bipolar binary masks with elements equal to 1 and −1, or (2) a unity mask together with one or more phase masks, or (3) a unity mask together with one pair of masks or more than one pair of masks having binary amplitudes of 0's and 1's, in which the masks in the pair are complementary to each other with respect to amplitude, or (4) one or more pairs of complementary masks with binary amplitudes of 0's and 1's without a unity mask.

A method of displaying a Computer Generated Holographic (CGH) image by a display, including setting pixel values of a Spatial Light Modulator (SLM) included in a Head Mounted Display (HMD), producing a interference based holographic image at a first location by projecting coherent light onto the SLM, and re-imaging the holographic image from the first location to form a holographic image in front of an eye of a viewer wearing the HMD. Related apparatus and methods are also described.

A light projection apparatus is provided comprising: a source of light; a switchable grating on a first substrate; and a diffractive optical element. Light is diffracted at least once by the switchable grating and is diffracted at least once by the DOE.

Provided are a method of displaying a digital holographic image and a digital hologram display apparatus, the method including generating and converting a digital hologram, recording the digital hologram in a spatial light modulator, radiating coherent parallel light to the spatial light modulator, removing an aliasing noise image, and implementing a reconstructed image reconstructed by the spatial light modulator.