A HUD system and light source apparatus can be manufactured with miniaturization at low cost. A head-up display apparatus includes: an image display apparatus generating image light to be projected; an optical system performing predetermined correction to the image light emitted from the image display apparatus; and a concave mirror reflecting the image light corrected by the optical system to project it onto a windshield or combiner. The image display apparatus includes: a solid light source; a collimating optical system converting, into parallel light, the light from the solid light source; a lighting optical system configured by an optical member that polarizes a direction of a light beam generated by the collimating optical system and simultaneously expands a width of the light beam; and a display apparatus, the image display apparatus being configured to be arranged across and opposite the optical system on an optical axis of the concave mirror.

A display device and a backlight module thereof are provided. The backlight module includes a collimated light source and a light guide plate. The collimated light source configured to generate a collimated light. The light guide plate has a bottom surface and a top surface opposite to each other, and a light entrance surface connected to ends of the bottom and top surfaces respectively for receiving collimated light from the collimated light source. The bottom surface inclines toward the top surface from the end of the bottom surface connected to the light entrance surface. A plurality of first grooves are disposed side by side on the bottom surface and respectively extend along the light entrance surface. The first groove has a first light receiving surface with a first end extending toward the top surface and inclining away from the light entrance surface. Compared to the first end of the first light receiving surface closer to the light entrance surface, the first end of the first light receiving surface farther from the light entrance surface has a vertical projection position on the light entrance surface that is closer to the top surface.

Provided is a compact light source device that can be manufactured at a low cost and is suitable as an illumination light source for a display device of an electronic device such as an HUD or an ultra-compact projector. This light source device includes a solid-state light source, a collimating optical system that converts light having exited the solid-state light source into a substantially collimated light; and a light guide that allows the light having exited the collimating optical system to enter and allows this light to exit in a direction that differs from a direction of entry. The light source device further includes a polarization converting element that aligns polarization directions of the light exiting the light guide into one direction.

The invention provides a diffractive waveguide element, waveguide stack, personal display and method of forming a viewable image. The element comprises a waveguide region (102) defined by two optical surfaces (102A/B) between which light can propagate by total internal reflections, the optical surfaces (102A/B) having surface profiles, and at least one diffractive grating capable of modifying the light field within the waveguide region (102). According to the invention, the surface profile of at least one of said optical surfaces (102A/B) is a staircase profile.

A light guide includes a light input surface, a first major surface orthogonal to the light input surface and a second major surface opposing the first major surface and forming a converging wedge with the first major surface. The second surface includes a plurality of doublet light extraction features closely-packed or separated by a land feature. Each doublet feature includes a first prism feature having a first shape and a second prism feature having a second shape and the second shape is different than the first shape.

A privacy display comprises a luminance-privacy arrangement and a contrast-privacy arrangement. In a privacy mode of operation, ambient light levels are detected and a visual security level is calculated. At and above a visual security level threshold the luminance-privacy arrangement is operable and below the threshold both the luminance-privacy and contrast-privacy arrangements are operable. Image quality for on-axis users is optimised and high levels of visual security are achieved for off-axis snoopers over a wide range of display illuminance conditions.

A waveguide body comprises a length from a first end to a second end along a longitudinal axis, and a coupling portion that comprises first and second coupling surfaces. The first and second coupling surfaces define, at least in part, an elongate coupling cavity along the entire length of the waveguide body and a surface located opposite the coupling cavity. The waveguide body further comprises first and second opposed sections extending along the length of the waveguide body. The first and second opposed sections further comprise respective first and second lower surfaces disposed at different first and second side section angles with respect to a first axis lying in a plane normal to the longitudinal axis. The first axis bisects the coupling portion. Among other things, such a waveguide may be included in a luminaire along with a light source.

A privacy display comprises a liquid crystal spatial light modulator, a switchable retarder and a passive compensation retarder arranged between a pair of polarisers. In a privacy mode of operation, on-axis light from the spatial light modulator is directed without change of image contrast, whereas off-axis light has reduced contrast to reduce the visibility of the display to off-axis snoopers over a wide polar angular range. In a wide angle mode of operation, the retardance of the switchable retarder is adjusted so that off-axis contrast is substantially unmodified.

A backlight module includes: light sources; a light guide plate disposed at a side of the light sources, the light guide plate including a second light guide portion disposed adjacent to the light sources and a first light guide portion disposed on a side of the second light portion away from the light sources, a thickness of the second light guide portion being greater than a thickness of the first light guide portion; and a back plate including a first back plate portion disposed at a side of the light sources away from the light guide plate and a second back plate portion disposed at a side of the light guide plate which is opposite to a light exit side of the light guide plate.

In one aspect, there is provided a display. The display may include a waveguide layer, a first active layer, a redirecting layer, and a lenset layer.