A holographic display apparatus capable of steering a location of a viewing window according to a location of an observer is disclosed. The holographic display apparatus includes a light source; a spatial light modulator configured to modulate incident light and thereby reproduce the holographic image; a spatial filter configured to transmit only the holographic image; an eye tracker configured to track a pupil location of an observer; and a controller configured to adjust locations of the light source and the spatial filter in response to a change in the pupil location of the observer received from the eye tracker. The controller is configured to move the light source and the spatial filter simultaneously in the same direction by the same distance.

A backlight device having a light guide, a first holographic optical element and a second holographic element are provided. The light guide plate guides light emitted by a light source towards the first holographic optical element. The first holographic optical element, which has a multi-layered structure, is provided on a first side of the light guide plate and reflects the light according to the wavelength ranges based on the characteristics of the multi-layered structure. The second holographic optical element, which concentrates light reflected by the first holographic optical element onto at least two points is provided on a second side of the light guide plate perpendicular to the first side.

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.

A projection system projects images onto a projection surface in, for example, a computer game head-mounted display (HMD). The light is projected through a spatial light modulator that contains a phase-only image of a Freeform Fourier Lens that is a combination of a Fresnel lens, an X-phase grating, a Y-phase grating, and a radial grating. The freeform lens is a condensing freeform lens that causes the gradual shrinking of portions of the laser-projected image, decreasing the perceived pixel pitch in at least one foveal area on the projection surface compared to a non-modulated laser image. The center positions of the Fresnel lens and radial grating can be changed in the X and Y axes, moving the condensed foveal areas in accordance with eye tracking of the user. In effect, the system projects a Foveated image that contains variable pixel pitch such that a user perceives a higher visual acuity in his gaze direction to the projected surface.

A method for optimally producing a holographic image using a Holographic Optical Element (HOE) and the HOE meant for controlling directions and divergences of light beams to impart system compactness. The system uses concave and convex lenses and other beam expanding, splitting, modulating and combining optics for realization of compactness and high throughput. The thin laser beam is split using a holographic optical element and a conventional beam splitter. A neutral density filter adjusts the intensity of a reference beam to match the intensity of an object beam so that high quality digital holograms can be recorded. Effects of vibrations are minimized by the compact optical design, by anti-vibration mounts, by mounting all the opto-mechanical components on a single rigid platform and by enclosing the system. An electro-optical sensor array records holograms digitally and an algorithm numerically reconstructs and further quantifies the results using a personal computer/laptop/tablet etc.

The present invention concerns a holographic display device incorporated in a timepiece device comprising at least one movable hand, having a light source at its peripheral end, and a watch glass comprising at least one hologram at its periphery, said light source being arranged on the hand so that it reconstructs said hologram when it moves into a predetermined angular sector.

Provided are a light guide plate, a backlight unit, and a holographic display apparatus including the backlight unit. The backlight unit includes a light source and a light guide plate including two or more layers configured to guide light from the light source, wherein the two or more layers are configured to control a ratio of light transmitted therethrough to light reflected thereby.

Examples are disclosed that relate to holographic near-eye display systems. One example provides a near-eye display device, comprising a diverging light source, an image producing dynamic digital hologram panel configured to receive light from the diverging light source and form an image. The near-eye display device also includes and a combiner comprising a holographic optical element positioned to receive light from the dynamic digital hologram panel and to redirect the light toward an eyebox, the holographic optical element being positioned between the eyebox and a view of an external environment to combine a view of the image formed by the dynamic digital hologram panel and the view of the external environment.

A holographic display and a method, performed by the holographic display, of forming a holographic image are disclosed. The holographic display includes an electrically addressable spatial light modulator (EASLM); a diffractive optical element (DOE) mask array arranged on the EASLM; and a controller configured to operate the holographic display to form a hologram image, wherein the controller is further configured to address the EASLM to backlight the DOE mask array required to form a set of hologram image voxels by turning on a corresponding EASLM pixel.

A backlight unit may include: a light source providing coherent light; a light guide plate having a light entrance surface on which light from the light source is incident and a light exit surface through which the light is output; a plurality of diffraction gratings (for example, a first input grating, a second input grating, and a third input grating) that are arranged in different regions of the light guide plate to sequentially diffract the light from the light source such that that the beam width of the light may increase as the light propagates in the light guide plate; and a diffraction grating (for example, an output grating) that diffracts and outputs the light having an increased beam width in a direction toward the outside of the light guide plate.