A tunable-liquid-crystal-grating-based holographic true 3D display system comprises a laser, a filter, a beam expander, a semi-transparent semi-reflective mirror, a spatial light modulator, a lens I, a diaphragm, a tunable liquid crystal grating, a polaroid, a signal controller, a lens II and a receiving screen. The laser, the filter and the beam expander are used for generating collimated incident light. The spatial light modulator is loaded with a hologram of a 3D object. The diaphragm is positioned behind the lens I for eliminating a high-order diffracted light in the holographic true 3D display. The tunable liquid crystal grating is located on the back focal plane of the lens I and on the front focal plane of the lens II, and the signal controller is used for synchronously controlling the voltage of the tunable liquid crystal grating and the generation and loading of the hologram.

A video communication system uses a light field display to present a holographic image of a remote scene (e.g., a hologram of a remote participant). The system may include a local light field display assembly and a controller. The controller generates display instructions based on visual data corresponding to a remote scene received from a remote image capture system (e.g., a remote light field display system). The display instructions cause the local light field display assembly to generate a holographic image of the remote scene.

A hologram display device includes a light source unit that emits light, a spatial light modulator that modulates the light emitted from the light source unit, and a random pinhole panel. The random pinhole panel includes a plurality of pinholes of a random position or a random size and is arranged in line with an output part of the spatial light modulator. In the hologram display device and the method of manufacturing the hologram display device, a position and size of a random pinhole on the random pinhole are not limited to inside each pixel of the spatial light modulator.

Disclosed herein a module controlling viewing window, a device for hologram display and a method for displaying hologram. The module controlling viewing window includes: a viewing window forming unit having a first reflective optical system that receives an incident light and forms a viewing window in a user's viewing region; and a viewing angle expanding unit having a second reflective optical system that is arranged in one direction on the viewing window forming unit and expands a viewing angle of the viewing window.

A beam expanding film includes a first material layer and a photonic crystal layer that expands a width of incident light and emits light having an expanded width. The photonic crystal layer includes a first material layer and a plurality of second material layers buried in the first material layer. A holographic display apparatus includes a backlight unit configured to provide coherent collimated light; a beam expanding film described above and facing the backlight unit; a flat panel arranged between the backlight unit and the beam expanding film to provide a hologram; and a lens configured to focus a holographic image on a space.

A holographic display apparatus includes a light guide plate including an input coupler and an output coupler, a holographic image generating assembly configured to generate a holographic image and provide the holographic image to the input coupler of the light guide plate, and an image processor configured to convert source image data based on a point spread function, which is obtained for each pixel of the holographic image on an image plane, to compensate for a blur of the holographic image output through the output coupler.

A replicator assembly includes reflective, transmissive, and transparent elements. The reflective element receives and reflects a hologram of a HUD system. The transmissive element includes a partially transmissive portion that receives a reflection of the hologram from the reflective element, outputs N replications of the hologram, and reflects N−1 replications of the hologram. The partially transmissive portion is implemented as a continuous transmission neutral density filter across different phase regions. The phase regions of the partially transmissive portion correspond respectively to the N replications. N is an integer greater than or equal to 2. The reflective element reflects the N−1 replications of the hologram. The transparent element is disposed between the reflective and transmissive elements and guides the N replications of the hologram between the reflective and transmissive elements. The reflective, transmissive and transparent elements are implemented as a replicator and collectively provide the N replications of the hologram.

A holographic display with a spatial light modulator coupled to a pupil-replicating lightguide is disclosed. The spatial light modulator provides a light beam with spatially modulated amplitude and/or phase. The light beam is replicated by the pupil-replicating lightguide into a plurality of portions. The portions interfere at an exit pupil to provide an image for direct observation by a user. An eye-tracking system may be provided to determine the position of the user pupils, and the spatial modulation of the light beam may be adjusted accordingly to make sure that the optical interference of the beam portions at the eye pupils provides the required image.

A holographic display apparatus and a holographic display method are provided. The holographic display apparatus determines a representative depth from 3D image data; calculates a computer generated hologram (CGH) corresponding to the representative depth on the 3D image data; obtains the modulated CGH by modulating a phase of the CGH to increase an eye box; modulates a light according to the modulated CGH and generates a hologram image; and forms the generated hologram image at the representative depth.

Provided is an augmented reality (AR) device based on a waveguide with a holographic diffractive grating structure and an apparatus for recording the holographic diffractive grating structure. The apparatus includes a light source, a beam splitter, a first amplitude filter and a first triangular prism that are arranged on a path of a first light beam, and a second amplitude filter and a second triangular prism that are arranged on a path of a second light beam, in which a first part of the first light beam passes through the first triangular prism without attenuation, a second part of the first light beam passes through the first triangular prism after being attenuated, and the second light beam passes through the second triangular prism after being attenuated, and the holographic diffractive grating structure is recorded between the first triangular prism and the second triangular prism.