A method of computing a hologram by determining the wavefronts at the approximate observer eye position that would be generated by a real version of an object to be reconstructed. In normal computer generated holograms, one determines the wavefronts needed to reconstruct an object; this is not done directly in the present invention. Instead, one determines the wavefronts at an observer window that would be generated by a real object located at the same position of the reconstructed object. One can then back-transforms these wavefronts to the hologram to determine how the hologram needs to be encoded to generate these wavefronts. A suitably encoded hologram can then generate a reconstruction of the three-dimensional scene that can be observed by placing one's eyes at the plane of the observer window and looking through the observer window.

An optical device (100) for forming a distribution of a three-dimensional light field comprises: an array (102) of unit cells (104), a unit cell (104) being individually addressable for switching the optical property of the unit cell (104) between a first and a second condition; wherein the unit cells (104) are configured to be selectively active or inactive and wherein the array (102) comprises at least a first and a second disjoint subset (110; 112; 114; 116), and wherein the unit cells (104) in a subset (110; 112; 114; 116) are configured to be jointly switched from inactive to active, wherein the active unit cells (104) are configured to interact with an incident light beam (106) for forming the distribution of the three-dimensional light field; and wherein the optical device (100) is configured to address inactive unit cells (104) for switching the optical property of unit cells (104).

Disclosed are a holographic display method and a holographic display device. The holographic display method includes: acquiring an area of Nth diffraction order corresponding to an eye position; according to the area of Nth diffraction order, calculating a holographic complex amplitude distribution corresponding to a window of Nth diffraction order to obtain window hologram information, a function of the holographic complex amplitude distribution being expressed by C(m,n)=A(m,n)*exp[−iφ(m,n)/N]; encoding the window hologram information; and according to the encoded window hologram information, loading the encoded window hologram information in the area of Nth diffraction order to display a hologram.

An optical combiner includes an optical substrate. An in-coupler grating is positioned to receive an incident light with a FOV and couple a first portion of the incident light into a first propagation path within the optical substrate and a second portion of the incident light into a second propagation path within the optical substrate. The first light portion includes light of a first color, while the second light portion excludes light of the first color. The optical combiner includes fold gratings to expand the first light portion and second light portion and direct the expanded light towards an out-coupler grating, which couples the expanded light out of the optical substrate at multiple exit pupils.

The present invention discloses a method that combines two different hologram origination processes in a single photoresist layer by using an interlayer to transfer structures exposed by electron beam lithography into overlapped with dot-matrix hologram areas, and fabricated holographic structures are replicated in multilayer polymer films. Dot-matrix technique is low cost process, which has high origination speed and can be used for the patterning of large areas of holograms with high diffraction efficiency. Electron beam lithography allows the formation of high resolution structures. The proposed manufacturing method allows combining these two technologies so that the final security device could contain electron beam patterned high resolution diffraction gratings, computer generated holograms, as well as dot-matrix laser patterned large hologram areas with high diffraction efficiency, providing an increased level of protection.

The invention relates to a display device for holographic reconstruction of two-dimensional and/or three-dimensional objects. The objects include a plurality of object points. The display device comprises an illumination unit, a spatial light modulator device and a separator. The illumination device emits sufficiently coherent light. Sub-holograms of object points to be displayed are encoded in pixels of the spatial light modulator device. The separator is provided for separating adjacent point spread functions in an eye of an observer generated by the sub-holograms of adjacent object points such that the adjacent point spread functions are mutually incoherent.

An integrated three-dimensional display includes a recording surface which includes a calculated element region in which phase components of light from light converging points of a holographic reconstructed image are calculated, and a phase angle recorded area for recording a phase angle calculated based on the phase components. The phase angle recorded area includes a plurality of monochromatic regions having a uneven structure surface. The phase angle is recorded in an overlap area in which the calculated element region and the phase angle recorded area overlap each other. Light converges on the light converging points at specific distances from the recording surface, the specific distances being determined for the respective light converging points even when light reflected from the plurality of monochromatic regions converges.

A method of holographic projection. The method comprises projecting at least one calibration image using a first colour holographic channel and a second colour holographic channel. Each calibration image comprises at least one light spot. The method comprises performing the following steps for each calibration image in order to determine a plurality of displacements vectors at a respective plurality of different locations on the replay plane. A first step comprises projecting the calibration image onto the replay plane using a first colour holographic channel by displaying a first hologram on a first spatial light modulator and illuminating the first spatial light modulator with light of the first colour. A second step comprises projecting the calibration image onto the replay using a second colour holographic channel by displaying a second hologram on a second spatial light modulator and illuminating the second spatial light modulator with light of the second colour. It may be said that the first and second hologram correspond to the calibration image. A third step comprises determining the displacement vector between the light spot formed by the first colour holographic channel and the light spot formed by the second colour holographic channel. A fourth step comprises pre-processing an image for projection using the second colour holographic channel in accordance with the plurality of determined displacement vectors.

A holographic display apparatus includes: a light source configured to emit light; a spatial light modulator configured to sequentially generate hologram patterns for modulating the light and to sequentially reproduce frames of hologram images based on the hologram patterns; and a controller configured to provide hologram data signals to the spatial light modulator, the hologram data signals being used to sequentially generate the hologram patterns. The controller is configured to further provide, to the spatial light modulator, diffraction pattern data signals for forming periodic diffraction patterns for adjusting locations of the hologram images to be reproduced on a hologram image plane, the diffraction pattern data signals being configured to move the periodic diffraction patterns on the spatial light modulator along a predetermined direction for each of the frames.

An optical device (100) for forming a distribution of a three-dimensional light field comprises: an array (102) of unit cells (104), a unit cell (104) being individually addressable for switching the optical property of the unit cell (104) between a first and a second condition; wherein the unit cells (104) are configured to be selectively active or inactive and wherein the array (102) comprises at least a first and a second disjoint subset (110; 112; 114; 116), and wherein the unit cells (104) in a subset (110; 112; 114; 116) are configured to be jointly switched from inactive to active, wherein the active unit cells (104) are configured to interact with an incident light beam (106) for forming the distribution of the three-dimensional light field; and wherein the optical device (100) is configured to address inactive unit cells (104) for switching the optical property of unit cells (104).