A display device according to embodiments of the present disclosure includes a determination unit to determine a display mode, a light generator to selectively irradiate a 2D light or a hologram 3D light, a spatial light modulator to selectively display a 2D image or a hologram 3D image, and a control unit that controls the light generator to selectively irradiate the 2D light or the hologram 3D light and controls the spatial light modulator to modulate the 2D light or the hologram 3D light irradiated from the light generator to display the 2D image or the hologram 3D image according to the display mode determined by the determination unit.

There is provided a method of projection using an optical element (502,602) having spatially variant optical power. The method comprises combining Fourier domain data representative of a 2D image with Fourier domain data having a first lensing effect (604a) to produce first holographic data. Light is spatially modulated (504,603a) with the first holographic data to form a first spatially modulated light beam. The first spatially modulated light beam is redirected using the optical element (502,602) by illuminating a first region (607) of the optical element (602) with the first spatially modulated beam. The first lensing effect (604a) compensates for the optical power of the optical element in the first region (607). Advantageous embodiments relate to a head-up display for a vehicle using the vehicle windscreen (502,602) as an optical element to redirect light to the viewer (505,609).

A holographic characterization and playback apparatus is provided, which includes a light source, an optical path-forming optical system for separating the light emitted from the light source into a probe light and a reference light of different polarizations, and combining optical paths of the probe light and the reference light.

A three-dimensional (3D) display system includes a reference spatial light modulator configured to generate a reference wavefront. The system also includes an object spatial light modulator configured to generate an object wavefront. The system further includes a Hogel basis display positioned between the reference spatial light modulator and the object spatial light modulator. The Hogel basis display is configured to receive the reference wavefront and the object wavefront. The Hogel basis display is also configured to generate a light field based at least in part on interference between the reference spatial light modulator and the object spatial light modulator.

An optical element is configured to be worn in front of an eye of a wearer. The optical element has two main surfaces and includes at least one holographic diffusive element having diffusive properties resulting from spatial variations of refractive index of said holographic diffusive element. The spatial variation of refractive index is greater than 0.001 at at least one given wavelength, on a distance less than 30 μm. An optical equipment includes the optical element and methods for recording a holographic medium onto an optical lens.

Provided are an improved holographic reconstruction apparatus and method. A holographic reconstruction method includes: obtaining an object hologram of a measurement target object; extracting reference light information from the obtained object hologram; calculating a wavenumber vector constant of the extracted reference light information, and generating digital reference light by calculating a compensation term of the reference light information by using the calculated wavenumber vector constant; extracting curvature aberration information from the object hologram, and then generating digital curvature in which a curvature aberration is compensated for; calculating a compensated object hologram by multiplying the compensation term of the reference light information by the obtained object hologram; extracting phase information of the compensated object hologram; and reconstructing 3-dimensional (3D) shape information and quantitative thickness information of the measurement target object by calculating the quantitative thickness information of the measurement target object by using the extracted phase information of the compensated object hologram.

A display apparatus includes a coherent light source, a display unit, a light-diffusing element, and at least one optical element. The coherent light source is configured to provide coherent light beams. The display unit is configured to form a three-dimensional image beam based on interference of the coherent light beams, wherein the three-dimensional image beam is imaged on an intermediate imaging surface after passing through the display unit. The light-diffusing element is located on the intermediate imaging surface, wherein a diffusion angle of the three-dimensional image beam is sequentially changed by passing through the light-diffusing element. The at least one optical element is located on a transmission path of the three-dimensional image beam from the light-diffusing element, and is configured to project the three-dimensional image light beam passing through the display unit out of the display apparatus to display a three-dimensional image.

An illumination device for illuminating a spatial light modulator device. Sub-holograms are used for encoding a hologram into the spatial light modulator device. The Illumination device includes at least one light source for emitting light for illuminating the spatial light modulator device and a beam shaping unit. The beam shaping unit provides a flat-top plateau-type distribution of an absolute value of a complex degree of mutual coherence of the light in a plane of the spatial light modulator device to be illuminated. The flat-top plateau-type distribution of the absolute value of the complex degree of mutual coherence has a shape that is at least similar to a shape of the largest sub-hologram used for encoding of object points into the spatial light modulator device.

A holographic display with an illumination device, an enlarging unit and a light modulator. The illumination device includes at least one light source and a light collimation unit, the light collimation unit collimates the light of the at least one light source and generates a light wave field of the light that is emitted by the light source with a specifiable angular spectrum of plane waves, the enlarging unit is disposed downstream of the light collimation unit, seen in the direction of light propagation, where the enlarging unit includes a transmissive volume hologram realising an anamorphic broadening of the light wave field due to a transmissive interaction of the light wave field with the volume hologram, and the light modulator is disposed upstream or downstream of the anamorphic enlarging unit, seen in the direction of light propagation.

A holographic projector includes a spatial light modulator, a light receiving member and a driver. The spatial light modulator is arranged to receive and represent a computer-generated hologram and spatially modulate light incident on the spatial light modulator to form a holographic reconstruction in accordance with the computer-generated hologram. The light receiving member is arranged to receive spatially modulated light along an optical axis from the spatial light modulator and the holographic reconstruction is formed on the light receiving member. The driver is coupled to the light receiving member to move the light receiving member in a plane. The driver is configured to move the light receiving member while maintaining an orientation of the light receiving member relative to the spatial light modulator substantially constant.