A pseudo speckle pattern generation apparatus includes a light source, a beam expander, and a spatial light modulator. The spatial light modulator has an intensity modulation distribution based on a pseudo speckle pattern calculated from a pseudo random number pattern and a correlation function, receives light output from the light source and increased in beam diameter by the beam expander, spatially modulates the received light according to the modulation distribution, and outputs modulated light.

A projection system and method includes a light source configured to emit a light in response to an image data; a phase light modulator configured to receive the light from the light source and to apply a spatially-varying phase modulation on the light; and a controller configured to determine, for a frame of the image data, a plurality of phase configurations, respective ones of the plurality of phase configurations corresponding to solutions of a phase algorithm and representing the same image with a different modulation pattern, and provide a phase control signal to the phase light modulator, the phase control signal configured to cause the phase light modulator to modulate the plurality of phase configurations in a time-divisional manner within a time period of the frame, thereby to project a series of subframes within the time period.

An Electrically Switchable Bragg Grating (ESBG) despeckler device comprising at least one ESBG element recorded in a hPDLC sandwiched between transparent substrates to which transparent conductive coatings have been applied. At least one of said coatings is patterned to provide a two-dimensional array of independently switchable ESBG pixels. Each ESBG pixel has a first unique speckle state under said first applied voltage and a second unique speckle state under said second applied voltage.

An Electrically Switchable Bragg Grating (ESBG) despeckler device comprising at least one ESBG element recorded in a hPDLC sandwiched between transparent substrates to which transparent conductive coatings have been applied. At least one of said coatings is patterned to provide a two-dimensional array of independently switchable ESBG pixels. Each ESBG pixel has a first unique speckle state under said first applied voltage and a second unique speckle state under said second applied voltage.

A method and display apparatus for reducing holographic speckle when displaying holographic images are described. A target image (10) is decomposed into input images (11). A first input image includes higher spatial frequency components of the target image and is imaged using a first display method (12) to generate a first holographic display image. The second input image includes lower spatial frequency components of the target image and is imaged using a second display method (12) to generate a second display image. The first and second display images are combined for display to a user. The second display method (12) is adapted to reduce holographic speckle or include no holographic speckle compared to the first holographic display method (12) thereby reducing holographic speckle in the combined display image (13).

A method and display apparatus for reducing holographic speckle when displaying holographic images are described. A target image (10) is decomposed into input images (11). A first input image includes higher spatial frequency components of the target image and is imaged using a first display method (12) to generate a first holographic display image. The second input image includes lower spatial frequency components of the target image and is imaged using a second display method (12) to generate a second display image. The first and second display images are combined for display to a user. The second display method (12) is adapted to reduce holographic speckle or include no holographic speckle compared to the first holographic display method (12) thereby reducing holographic speckle in the combined display image (13).

A projection apparatus including a liquid crystal on silicon panel and a processor is provided. The liquid crystal on silicon panel is configured to display a plurality of phase images. The phase images include a first phase image and a second phase image. The processor is coupled to the liquid crystal on silicon panel. The processor is configured to generate and output the phase images to drive the liquid crystal on silicon panel to display the phase images. The processor generates the first phase image according to a first phase information, and the processor generates the second phase image according to the first phase image.

A pseudo speckle pattern generation apparatus includes a light source, a beam expander, and a spatial light modulator. The spatial light modulator has an intensity modulation distribution based on a pseudo speckle pattern calculated from a pseudo random number pattern and a correlation function, receives light output from the light source and increased in beam diameter by the beam expander, spatially modulates the received light according to the modulation distribution, and outputs modulated light.

A head-up display is described. A spatial light modulator is arranged to display a diffractive pattern of first picture content and/or second picture content. A screen assembly has first and second diffusers arranged in a stepped configuration so that the first diffuser is spatially offset from the second diffuser by a perpendicular distance. A light source is arranged to illuminate the diffractive pattern such that the first picture content is formed on the first diffuser and/or the second picture content is formed on the second diffuser. An optical system comprising at least one optical element having optical power is arranged so that the first and second diffusers have different object distances to the optical system.

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.