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.

Image persistence of the spatial light modulator is suppressed. A projection device (1) includes: an illumination optical system (12) that emits light; an information processing unit (20) that generates a hologram pattern based on an input image; a spatial light modulator (14) that forms the hologram pattern generated by the information processing unit and transmits light emitted by the illumination optical system; and a projection optical system (16) that projects an output of the spatial light modulator onto a projection surface and projects an output image, and the information processing unit generates the new hologram pattern obtained by shifting the hologram pattern in a predetermined direction for every predetermined frame.

An optical assembly comprises a light source, a light-modulation element for modulating light from the light source, and a terminal optical element for directing modulated light from the optical assembly. Optical elements are provided to guide the light in a first path from the light source to the light-modulation element and to guide the modulated light in a second path from the light-modulation element to the terminal optical element. The first and second paths are of similar shape, for example a c-shape, and are arranged in a nested configuration.

An optical assembly comprises a light source, a light-modulation element for modulating light from the light source, and a terminal optical element for directing modulated light from the optical assembly. Optical elements are provided to guide the light in a first path from the light source to the light-modulation element and to guide the modulated light in a second path from the light-modulation element to the terminal optical element. The first and second paths are of similar shape, for example a c-shape, and are arranged in a nested configuration.

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 system comprises an image processor, a hologram calculator and a display driver. The image processor is arranged to determine first and second secondary images by sampling the pixel values of a primary image at a regular array of sampling positions. The hologram calculator is arranged to determine a hologram of each secondary image. The display driver is arranged to display each hologram in rapid succession on a display device, first and second times, so as to reconstruct each secondary image from the respective hologram such that respective first and second arrays of image pixels corresponding to the primary image are perceivable. Image pixels of the reconstruction of the second secondary image are interposed between image pixels of the reconstruction of the first secondary image in the first direction.

There is described herein a diffuser assembly comprising a leaf spring, diffuser and at least one actuator. The leaf spring is arranged as a rectangular frame having a width, x, and height, y. The diffuser is suspended by the frame such as within the frame. The at least one actuator arranged to move, such as translate, the diffuser. The assembly is arranged such that the leaf spring provides in-plane (x-y plane) stiffness, k.sub.x and k.sub.y, less than the out-of-plane (z-direction) stiffness, k.sub.z.

There is described herein a diffuser assembly comprising a leaf spring, diffuser and at least one actuator. The leaf spring is arranged as a rectangular frame having a width, x, and height, y. The diffuser is suspended by the frame such as within the frame. The at least one actuator arranged to move, such as translate, the diffuser. The assembly is arranged such that the leaf spring provides in-plane (x-y plane) stiffness, k.sub.x and k.sub.y, less than the out-of-plane (z-direction) stiffness, k.sub.z.

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.

A laser beam (L50) generated by a laser light source (50) is reflected by a light beam scanning device (60) and irradiated onto a hologram recording medium (45). On the hologram recording medium (45), an image (35) of a scatter plate is recorded as a hologram by using reference light that converges on a scanning origin (B). The light beam scanning device (60) bends the laser beam (L50) at the scanning origin (B) and irradiates the laser beam onto the hologram recording medium (45). At this time, scanning is carried out by changing a bending mode of the laser beam with time so that an irradiation position of the bent laser beam (L60) on the hologram recording medium (45) changes with time. Regardless of an irradiation position of the beam, diffracted light (L45) from the hologram recording medium (45) produces a reproduction image (35) of the scatter plate on the spatial light modulator (200). The modulated image of the spatial light modulator (200) is projected onto a screen (400) by a projection optical system (300).