A holographic projector is provided. The holographic projector includes a display device arranged to form a holographic wavefront by spatially modulating light in accordance with a hologram displayed thereon, a waveguide having an input arranged to receive the holographic wavefront, and a first surface and a second surface arranged to waveguide the holographic wavefront therebetween. The first surface of the waveguide is partially reflective-transmissive such that a plurality of replicas of the holographic wavefront are emitted therefrom. A size of the hologram is less than a size of an entrance pupil of a viewing system for receiving the holographic wavefront from the first surface of the waveguide and the hologram includes a first sub-hologram of a first region of an image adjoined to a second sub-hologram of a second region of the image.

A display system and a method of adjusting a display system are disclosed. A first plurality of pixels is arranged to display a first hologram, receive light of a first wavelength, and output spatially-modulated light according to the first hologram, along a first optical path. A first Fourier transform lens on the first optical path forms a first holographic reconstruction at a replay plane. A second plurality of pixels is arranged to display a second hologram, receive light of a second wavelength, and output spatially modulated light according to the second hologram, along a second optical path. A second Fourier transform lens on the second optical path forms a second holographic reconstruction at the replay plane. A first optical element on the first optical path is arranged to receive the output light from a first part of the first optical path and direct it along a second part of the first optical path to the replay plane. A second optical element on the second optical path is arranged to receive the output light of the second wavelength from a first part of the second optical path and direct it along a second part of the second optical path to the replay plane. The length of the first part of the first optical path is not equal to the length of the first part of the second optical path. The first part of the first optical path may he substantially collinear with the first part of the second optical path.

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.

A method for displaying a hologram to a variable direction including using circuitry to determine a direction from a holographic projector to a viewer for projecting a hologram to a viewer, and projecting a hologram in the determined direction, in which the projecting the hologram includes reflecting from a same mirror as the determining the direction of the viewer, and the circuitry controls the projecting the hologram to a direction corrected for a difference in direction between a projecting unit and a tracking unit relative to the mirror. Related apparatus and methods are also described.

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.

The present disclosure relates to the field of display technology and provides an addressing method of a spatial light modulator, a holographic display device and a control method thereof, which can simplify the addressing process of the spatial light modulator. The addressing method of the spatial light modulator comprises the steps of: dividing the spatial light modulator to obtain one or more modulation regions, each modulation region comprising M loading subregions, and each loading subregion comprising at least one pixel unit, wherein M12, and M is a positive integer; and addressing one loading subregion of each modulation region within a frame so as to load holographic data of a frame of a hologram to all the pixel units of all the addressed loading subregions.

A holographic projector comprises an image processing engine, a hologram engine, a display engine and a light source. The image processing engine is arranged to receive a source image for projection and generate a plurality of secondary images from a primary image based on the source image. The source image comprises pixels. Each secondary image may comprise fewer pixels than the source image. The plurality of secondary images are generated by sampling the primary image. The hologram engine is arranged to determine, such as calculate, a hologram corresponding to each secondary image to form a plurality of holograms. The display engine is arranged to display each hologram on the display device. The light source is arranged to Illuminate each hologram during display to form a holographic reconstruction corresponding to each secondary image on a replay plane. The primary image is selected from the group comprising: the source image and an intermediate image.

A display system comprising a first plurality of pixels, a second plurality of pixels, a first Fourier transform lens and a second Fourier transform lens. The first plurality of pixels is arranged to display first holographic data corresponding to a first holographic reconstruction and receive light of a first wavelength. The a second plurality of pixels is arranged to display second holographic data corresponding to a second holographic reconstruction and receive light of a second wavelength. The first Fourier transform lens is arranged to receive spatially modulated light having a first wavelength from the first plurality of pixels and perform an optical Fourier transform of the received light to form the first holographic reconstruction at a replay plane, wherein the first holographic reconstruction is formed of light at the first wavelength. The second Fourier transform lens is arranged to receive spatially modulated light having a second wavelength from the second plurality of pixels and perform an optical Fourier transform of the received light to form the second holographic reconstruction at the replay plane, wherein the second holographic reconstruction is formed of light at the second wavelength. The optical path length from the first Fourier transform lens to the replay plane is not equal to the optical path length from the second Fourier transform lens to the replay plane.

A method of calculating a map in real-time includes receiving a calibrated map including a plurality of mappings. Each mapping is for transforming a respective two-dimensional coordinate of an array of two-dimensional coordinates to compensate for distortion at a predetermined temperature. The method includes receiving an array of vectors including a vector for each two-dimensional coordinate. The method includes receiving a current temperature of the holographic projector. The method includes determining a scaling factor based on the difference between the current temperature and the predetermined temperature. The method includes calculating a modified map based on the current temperature by, for each coordinate of the array of two-dimensional coordinates: multiplying the vector that relates to the respective coordinate of the array of two-dimensional coordinates by the scaling factor to output a scaled vector; applying the scaled vector to the respective mapping of the calibrated map; and outputting the modified map.

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.