A face-lit waveguide illumination system employing a planar sheet of an optically transmissive material. A strip of side-emitting LEDs is positioned adjacent to a major surface of the planar sheet and optically coupled to the planar sheet. The planar sheet is configured to guide light using optical transmission and total internal reflection. Light extraction features located along the prevailing path of light propagation extract light from the planar sheet and emit the light towards a surface normal direction.

A backlight module, a manufacturing method thereof, a display device and a light guide device are provided. The backlight module includes: a light guide structure, including a volume grating layer, the volume grating layer including a plurality of volume grating portions and a light guide portion between adjacent volume grating portions, the plurality of volume grating portions being configured to introduce a beam of a specific wavelength into the light guide portion; and a light extraction structure, located on a light exit side of the light guide structure, wherein a refractive index of the light guide structure is greater than a refractive index of the light extraction structure, and an incident angle of the beam introduced into the light guide portion on a plane where the light guide portion is located is not less than a total reflection critical angle of the light guide structure.

Provided a backlight unit including a light source and a light guide structure configured to guide the light emitted from the light source, the light guide structure includes a first coupler layer including a first output coupler configured to expand light in a first direction and output the expanded light in the first direction to the outside of the light guide structure, and a first expansion coupler configured to expand the light in a second direction perpendicular to the first direction and provide the expanded light in the second direction to the first output coupler, and a second coupler layer including a second output coupler configured to expand light in the first direction and output the expanded light to the outside of the light guide structure, and a second expansion coupler configured to expand light in the second direction and provide the expanded light to the second output coupler.

A fingerprint recognition system may comprise: a display panel configured to display an image on a screen; a light source device configured to irradiate light onto a transparent substrate disposed on the screen of the display panel; an image sensor configured to obtain a fingerprint image with light reflected from a fingerprint contacting the transparent substrate on the screen; and an image sensor controller configured to control an exposure time of the image sensor to obtain the fingerprint image based on a contrast ratio of the fingerprint image.

A device for backlighting a display in day- or night-vision mode includes a light guide with a cuboid shape and having an output face, and a lateral input prism having three rectangular lateral faces, at least one of the rectangular lateral faces being optically coupled to the lateral input face, and another of the rectangular lateral faces being semi-reflective; a first plurality of light emitting diodes arranged on a first carrier and configured to emit light in a first direction orthogonal to the first carrier towards one of the rectangular lateral faces; a second plurality of light emitting diodes arranged on a second carrier and configured to emit light in a second direction orthogonal to the second carrier towards another of the rectangular lateral faces; and an optical filter configured to modify the light emitted by one of the first and second plurality of light emitting diodes suitable for use in night-vision equipment.

A light guide module and an augmented reality (AR) apparatus are disclosed. The AR apparatus includes a display module and the light guide module. The light guide module includes a first light guide plate and a second light guide plate. The first light guide plate has a light receiving area for receiving optical input light with a predetermined incident angle and a light outputting area for outputting optical input light. The second light guide plate is disposed on the first light guide plate, and has dichroic surfaces for selectively transmitting or reflecting the optical input light.

Image light is introduced into a light guide through a collimating optical system, reflected by an incident side reflective surface (101) in a substrate (100), and repeatedly reflected between a first surface and a second surface (100a, 100b). The image light reaches a plurality of emission side reflective surfaces (102a to 102c) that constitute a beam splitter. The incident side reflective surface (101) and the emission side reflective surfaces (102a to 102c) are arranged in parallel. Therefore, with respect to the image light (L1, L2) derived from the image light emitted from the same position on a display surface of a display unit and incident on the substrate 100 at the same incident angle 1, the emission angle 2 of the image light (L1, L2) emitted from the substrate (100) becomes equal in both cases when the light is reflected one time by the incident side reflective surface (101) and one time by the emission side reflective surface (102a) and when the light is reflected two times by the incident side reflective surface (101) and two times by the emission side reflective surface (102a). As a result, it is possible to reduce the generation of a ghost image, which in turn can improve the visibility of a virtual image.

A light-guide optical element (LOE) includes a transparent substrate having two parallel major external surfaces for guiding light within the substrate by total internal reflection (TIR). Mutually parallel internal surfaces within the LOE are provided with a structural polarizer which is transparent to light polarized parallel to a primary polarization transmission axis, and is partially or fully reflective to light polarized perpendicular to the primary polarization transmission axis. By suitable orientation of the polarization axis of successive internal surfaces together with the polarization mixing properties of TIR and/or use of birefringent materials, it is possible to achieve the desired proportion of coupling-out of the image illumination from each successive facet.

[Problem] To propose a head-mounted display capable of restraining deformation or breakage of a connection member caused by concentration of an external force on the connection member. [Solution] A head-mounted display includes a frame worn on the head of a viewer and having a front part disposed in front of the viewer, and an image display device connected to a central part of the front part. The image display device includes two right and left optical modules each including an image generation device and a light guide member that is connected to the image generation device and is disposed closer as a whole to a center of the face of the viewer than the image generation device, and includes a connection member connecting the image display device to the front part. A part of the image display device is disposed so as to face a part of the front part in a front-rear direction with a predetermined gap interposed therebetween.

An optical grating component may include a substrate, and an optical grating, the optical grating being disposed on the substrate. The optical grating may include a plurality of angled structures, disposed at a non-zero angle of inclination with respect to a perpendicular to a plane of the substrate, wherein the plurality of angled structures are arranged to define a variable depth along a first direction, the first direction being parallel to the plane of the substrate.