A method of holographic projection includes projecting at least one calibration image. The method includes performing the following steps for each calibration image in order to determine a plurality of displacements vectors at a respective plurality of different locations on the replay plane: projecting the calibration image onto the replay plane using a first colour holographic channel by displaying a first hologram on a first spatial light modulator and illuminating the first spatial light modulator with light of the first colour; projecting the calibration image onto the replay using a second colour holographic channel by displaying a second hologram on a second spatial light modulator and illuminating the second spatial light modulator with light of the second colour, the first and second hologram corresponding to the calibration image; determining the displacement vector between the light spot formed by the first colour holographic channel and the light spot formed by the second colour holographic channel; and pre-processing an image for projection using the second colour holographic channel in accordance with the plurality of determined displacement vectors.

The invention relates to a light modulation device for a display for representing two- and/or three-dimensional image content or image sequences. The light modulation device comprises a light modulator and a controller. The phase and/or the amplitude of a light wave field, which is substantially collimated, can be varied by means of the light modulator depending on the location of the light modulator. The light modulator can be actuated by means of the control device. According to the invention, in the direction of propagation of the light wave field, at least one diffracting unit is arranged downstream of the light modulator. The diffracting unit has a variable diffracting structure. By means of the diffracting structure, the light wave field varied by the light modulator can be diffracted in a variable and predeterminable manner. Further, the present invention relates to a display and a method for producing a light modulation device.

Electro-holographic light field generator devices comprising surface acoustic wave (SAW) optical modulators are disclosed that employ multiple output couplers. These output couplers might be distributed along waveguides of the SAW modulators, within output coupling regions. Each of these output couplers can be configured for directing an incident leaky mode light at different output angles. In some cases, it may be desirable to employ the output couplers to function as different sub-pixels, to provide light to different viewing directions. The output couplers may be mirrors, volume gratings, chirped gratings, reflection gratings, two dimensional gratings, and/or transmission gratings. The output couplers may be angled so that the coupling output fans for each optical modulator are offset from the waveguide for that optical modulator.

A system and method for light field generation is disclosed. A proposed holographic display system encodes views of a scene into surface acoustic waves (SAW signals) that propagate along waveguides of SAW modulators and/or optical signals propagating in the waveguides. Each view provides a different perspective of the scene when the views are projected as light fields out of the SAW modulators and are viewed at different locations by an observer. In some examples, the system encodes the brightness information for each view into the light signals.

A holographic display panel comprises a plurality of display units, each display unit comprises at least two adjacent pixels, each pixel comprises: a plurality of sub-pixels; and a plurality of phase plates. Diffractive angles of light coming out of the phase plates corresponding to the sub-pixels in a same pixel are the same, a diffractive angle of first light coming out of the phase plates corresponding to a first pixel in one of the display units is different from a diffractive angle of second light coming out of the phase plates corresponding to a second pixel that is different from the first pixel but in the same display unit, and a reverse extension line of the first light and a reverse extension line of the second light intersect at an image plane position.

A head-mounted display device comprises a rendering engine configured to generate a hologram representative of a three-dimensional object. The hologram includes depth information that causes the three-dimensional object to be rendered with a focus that is determined by the depth information. The device also includes a spatial light modulator that modulates light from a light source as indicated by the hologram. A switchable hologram comprises multiple stacked switchable gratings. Each of the stacked switchable gratings is associated with one or more resulting exit pupil locations on a viewing surface. The system also comprises an eye tracker configured to map a viewing direction of a user's eye to a viewing location on the viewing surface. A processor is configured to activate a particular switchable grating within the switchable transmission hologram that is associated with an exit pupil location that aligns with the viewing location.

Electro-holographic light field generator devices comprising surface acoustic wave (SAW) optical modulators are disclosed that employ multiple output couplers. These output couplers might be distributed along waveguides of the SAW modulators, within output coupling regions. Each of these output couplers can be configured for directing an incident leaky mode light at different output angles. In some cases, it may be desirable to employ the output couplers to function as different sub-pixels, to provide light to different viewing directions. The output couplers may be mirrors, volume gratings, chirped gratings, reflection gratings, two dimensional gratings, and/or transmission gratings. The output couplers may be angled so that the coupling output fans for each optical modulator are offset from the waveguide for that optical modulator.

A head-mounted display device comprises a rendering engine configured to generate a hologram representative of a three-dimensional object. The hologram includes depth information that causes the three-dimensional object to be rendered with a focus that is determined by the depth information. The device also includes a spatial light modulator that modulates light from a light source as indicated by the hologram. A switchable hologram comprises multiple stacked switchable gratings. Each of the stacked switchable gratings is associated with one or more resulting exit pupil locations on a viewing surface. The system also comprises an eye tracker configured to map a viewing direction of a user's eye to a viewing location on the viewing surface. A processor is configured to activate a particular switchable grating within the switchable transmission hologram that is associated with an exit pupil location that aligns with the viewing location.

Methods and apparatus to calibrate spatial light modulators are disclosed. Examples include processor circuitry to execute and/or instantiate instructions to provide a greyscale image to a spatial light modulator (SLM) to define voltages to be applied to individual pixels of the SLM. The voltages associated with pixel values in the greyscale image. The pixel values arranged in a double-slit grating pattern. The SLM to produce an interference pattern based on the double-slit grating pattern. The processor circuitry is to determine a phase difference between first and second gratings of the double-slit grating pattern based on the interference pattern. The processor circuitry is to generate a phase curvature based on the phase difference.

This disclosure relates to a stimulus-responsive dynamic meta-holographic device. According to an aspect of the disclosure, a stimulus-responsive dynamic meta-holographic device can be provided, which includes a metasurface in which a plurality of nanostructures are provided; wherein in the metasurface is provided a liquid crystal layer comprising a plurality of cells that may be altered in arrangements by outer stimulus, wherein the liquid crystal layer, is configured to alter the polarization state of the transmitted beam penetrating the liquid crystal layer as the arrangements of the cells are altered by outer stimulus.