A method for adjusting the apparent brightness of a computer-generated hologram display is disclosed. The method comprises: receiving source data representative of a scene to be displayed as a hologram; determining hologram data to display a computer-generated hologram representing the scene; determining a scene energy based on the source data, the scene energy being quantised using a scale which is non-linear and which has a closer spacing between values in a mid-section of the scale than between values towards a minimum and a maximum of the scale; associating the scene energy with the hologram data; controlling a holographic display according to the hologram data and simultaneously controlling an output power of an illumination source of the holographic display according to the scene energy. A holographic display apparatus implementing the method is also disclosed.

There is disclosed herein a liquid crystal on silicon spatial light modulator, “LCoS SLM”, device arranged for in-plane switching. The LCoS SLM device comprises: a silicon backplane (1501); a transparent substrate (1581); a liquid crystal layer (1571); an electrode structure (1505, 1507) and a reflective component (1561, 1551). The liquid crystal layer (1571) is interposed between the silicon backplane (1501) and the transparent substrate (1581). The electrode structure (1505, 1507) is formed on the silicon backplane (1501) for generating an electric field in the liquid crystal layer (1571). The electric field is substantially parallel to the silicon backplane (1501). The reflective component (1551, 1561) is opposing the transparent substrate (1581).

A backlight device includes: a light source to emit coherent light; an optical path difference generator on the light source, the optical path difference generator including an incident surface and a plurality of light emitting surfaces, the light emitting surfaces being parallel to the incident surface and having different separation distances from the incident surface; a light condenser on the optical path difference generator; a diffuser on the light condenser; and a collimator on the diffuser.

In described examples, a system (e.g., a projection system) can include a diffractive optical element adapted to be illuminated by at least one coherent light beam. A lens array is coupled to receive a diffracted beam of light from the diffractive optical element. The lens array includes a first and a second array lens. The first array lens is coupled to receive a first sector of a pattern of illumination of the diffracted beam of light, and the second array lens is coupled to receive a second sector of the pattern of illumination of the diffracted beam of light. A spatial light modulator is coupled to receive overlapping diffracted beams of light from the first and second array lenses to form an image beam.

A holographic image generation system including a spatial light modulator; a light source; a temporal modulator; a light sensor and a demodulator. The spatial light modulator has pixels. The light source illuminates the spatial light modulator. The temporal light modulator modulates an output intensity of the light source over time to encode holographic data representing a hologram. The light sensor is associated with a spatial light modulator and receives light from the light source and generates a signal representative of the output intensity of the light source. The demodulator is connected to the light sensor to receive the signal. The demodulator decodes the signal to obtain the holographic data. The demodulator is connected to the spatial light modulator to set the pixels of the spatial light modulator in accordance with the holographic data to display the hologram ready for illumination by the light source to form a holographic reconstruction.

An image projector arranged to project an image onto a display plane. The image projector comprises a processing engine, a display device, an optical element and a light source. The processing engine outputs a computer-generated diffractive pattern comprising a hologram of an image for projection and a lens function corresponding to a lens having a first optical power. The display device is arranged to display the computer-generated diffractive pattern. The optical element is disposed between the display device to the display plane. The optical element has second optical power. The light source is arranged to provide off-axis illumination of the display device in order to spatially-modulated light in accordance with the hologram and lens function. The lens function of the computer-generated diffractive pattern and the optical element collectively perform a hologram transform of the hologram such that a reconstruction of the image is formed on the display plane.

There is provided a holographic projector comprising a processing engine, spatial light modulator (403B), light source (401B) and light-receiving surface (405B). The processing engine outputs a computer-generated diffractive pattern defining a propagation distance to an image plane. The spatial light modulator displays the computer-generated diffractive pattern. The light source illuminates the spatial light modulator at an angle of incidence (theta) greater than zero. The light-receiving surface receives spatially-modulated light from the spatial light modulator. The light-receiving surface is substantially parallel to the spatial light modulator (alpha-theta). The light-receiving surface is separated from the spatial light modulator by the propagation distance defined by the computer-generated diffractive pattern.

A method and system for improving the control of a holographic projection system in order to meet, or to attempt to meet, one or more targets or aims for a holographically reconstructed image that is produced by the holographic projection system. The target, or aim, may concern the luminance of part or all of the holographically reconstructed image.

There is disclosed herein an image projector arranged to project an image onto a display plane. The image projector comprises a processing engine, a display device, an optical element and a light source. The processing engine is arranged to output a computer-generated diffractive pattern comprising a hologram of an image for projection and a lens function corresponding to a lens having a first optical power. The display device is arranged to display the computer-generated diffractive pattern. The optical element is disposed between the display device to the display plane. The optical element has second optical power. The light source is arranged to provide off-axis illumination of the display device in order to spatially-modulated light in accordance with the hologram and lens function. The lens function of the computer-generated diffractive pattern and the optical element collectively perform a hologram transform of the hologram such that a reconstruction of the image is formed on the display plane. The display device is tilted with respect to the optical element by a first angle greater than zero. The display plane is tilted with respect to the optical element by a second angle greater than zero. The second angle is less than the first angle.

A backlight device includes: a light source to emit coherent light; an optical path difference generator on the light source, the optical path difference generator including an incident surface and a plurality of light emitting surfaces, the light emitting surfaces being parallel to the incident surface and having different separation distances from the incident surface; a light condenser on the optical path difference generator; a diffuser on the light condenser; and a collimator on the diffuser.