G03H2001/0816

Holographic projector
11372287 · 2022-06-28 · ·

There is provided a holographic projector comprising a reflective liquid crystal display device. The reflective liquid crystal display device comprises a light-modulating layer between a first substrate and a second substrate substantially parallel to the first substrate. The light-modulating layer comprises planar-aligned nematic liquid crystals having positive dielectric anisotropy. The first substrate is substantially transparent and comprises a first alignment layer arranged to impart a first pre-tilt angle θ.sub..Math. on liquid crystals proximate the first substrate, wherein θ.sub.1>5°. The second substrate is substantially reflective and comprises a second alignment layer arranged to impart a second pre-tilt angle Θ.sub.2 on liquid crystals proximate the second substrate, wherein θ.sub.2>5°. The reflective liquid crystal display device further comprises a plurality of pixels defined on the light-modulating layer having a pixel repeat distance x, wherein x≤10 μm. The distance d between inside faces of the first substrate and second substrate satisfies 0.5 μm≤d≤3 μm, and the birefringence of the liquid crystal Δη≥0.20. The holographic projector further comprises a display driver arranged to drive the reflective liquid crystal display device to display a hologram by independently-driving each pixel at a respective modulation level selected from a plurality of modulation levels having a phase modulation value.

METHOD OF DISPLAYING A HOLOGRAM ON A DISPLAY DEVICE COMPRISING PIXELS
20220197215 · 2022-06-23 ·

There is provided a holographic projector comprising a hologram engine and a controller. The hologram engine is arranged to provide a hologram comprising a plurality of hologram pixels. Each hologram pixel has a respective hologram pixel value. The controller is arranged to selectively-drive a plurality of light-modulating pixels so as to display the hologram. Displaying the hologram comprises displaying each hologram pixel value on a contiguous group of light-modulating pixels of the plurality of light-modulating pixels such that there is a one-to-many pixel correlation between the hologram and the plurality of light-modulating pixels.

REAL TIME HOLOGRAPHY USING LEARNED ERROR FEEDBACK
20220197214 · 2022-06-23 · ·

Techniques related to generating holographic images are discussed. Such techniques include application of a machine learning model to the target image to generate data that is used to enable the determination of a phase pattern via a wave propagation model. The wave propagation model is used to generate holographic data, which is then adjusted according to one or more constraints associated with the holographic display that will be used to generate a holographic image based on the adjusted holographic data.

Totagraphy: Coherent Diffractive/Digital Information Reconstruction by Iterative Phase Recovery Using Special Masks
20220187138 · 2022-06-16 ·

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.

METHOD AND HOLOGRAPHIC APPARATUS FOR THE THREE-DIMENSIONAL REPRESENTATION OF SCENES
20220179360 · 2022-06-09 ·

An apparatus and method for the three-dimensional representation of scenes comprising an illumination device and a spatial light modulation device for modulating incident light. A hologram is encoded into the spatial light modulation device and the hologram is composed of individual sub-holograms, in which an object point of an object of the scene to be reconstructed by the hologram is encoded in each case. The spatial light modulation device is illuminated with substantially coherent light by the illumination device in at least one illumination section. An amplitude distribution and a phase distribution for representing the scene and amplitude values and phase values derived therefrom are determined for encoding the spatial light modulation device. The amplitude of the light incident on the spatial light modulation device in the respective illumination section is set based on at least one parameter at least determined from the amplitude values in this illumination section.

Adjustably multifocal 3D holographic display system

A three-dimensional (3D) holographic display system includes a projector that generates an image with a form of spatially varying modulation on a light beam; holographic processor that performs a holographic method on the image generated by the projector; and memory device that stores holographic data generated in a process of performing the holographic method by the holographic processor. An amplitude of a light field is adaptively replaced by the holographic processor according to significance of respective areas of the image.

Deep computational holography

Techniques related to generating holographic images are discussed. Such techniques include application of a hybrid system including a pre-trained deep neural network and a subsequent iterative process using a suitable propagation model to generate diffraction pattern image data for a target holographic image such that the diffraction pattern image data is to generate a holographic image when implemented via a holographic display.

OPERATION METHOD FOR DIGITAL HOLOGRAM IMPLEMENTATION DEVICE

Provided is an operation method for a digital hologram implementation device including a backlight and a spatial light modulator, the operation method including setting an initial phase value of an optical signal to a remedy phase, computing a reduced phase based on the remedy phase, correcting the remedy phase based on a difference between the reduced phase and a preset optimized phase, determining whether the corrected remedy phase is a stabilized phase, performing forward propagation on the stabilized phase and an amplitude of the optical signal, correcting the amplitude of the optical signal, performing backward propagation on the corrected amplitude and the stabilized phase, and determining whether a phase derived by the backward propagation is an optimized phase.

Method and apparatus for processing holographic image

Provided are methods of processing a holographic image and apparatuses using the methods. A method includes obtaining image data with respect to a three-dimensional (3D) object, obtaining interference patterns in a computer-generated hologram (CGH) plane by performing a Fourier transform on the image data, and generating a CGH with respect to the 3D object based on the interference patterns, wherein the Fourier transform is performed based on a focal length of an eye lens of an observer.

Holographic projector
11307534 · 2022-04-19 · ·

There is provided a holographic projection system arranged to project light to a rectangular replay field. The holographic projection system comprises: a spatial light modulator, comprising an array of pixels, arranged to receive a computer-generated hologram and output spatially-modulated light forming a holographic reconstruction at the rectangular replay field, wherein each pixel is rectangular; and a light source arranged to illuminate the plurality of pixels to form the spatially-modulated light forming a holographic reconstruction at the replay field, wherein the rectangular replay field is spatially separated from the spatial light modulator and the aspect ratio of the rectangular replay field is substantially equal to the aspect ratio of each pixel but orthogonally orientated.