Light waveguide and display device

Abstract

The invention relates to a light waveguide. The light waveguide includes a light waveguide body, wherein the light waveguide body includes a beam coupling-in region and a beam coupling-out region, thebeam coupling-in region is provided with a coupling-in grating and configured to couple a beam into the light waveguide body and make the beam propagate in the light waveguide body in a totally reflective manner, the beam coupling-out region is provided with a coupling-out grating, is configured to couple the beam propagated to the beam coupling-out region out of the light waveguide body and makes the beam not undergo secondary diffraction at the coupling-in the grating and has a continuous expansion exit pupil, and the coupling-out grating includes a transmissive coupling-out grating and a reflective coupling-out grating disposed on two sides of the light waveguide body parallel to the beam propagation direction. The invention further relates to a display device. Through arranging the transmissive coupling-out grating at the light outgoing surface of the light waveguide body and the reflective coupling-out grating on the first surface, the continuous expansion exit pupil can be obtained while the beam is guaranteed not undergo secondary diffraction at the coupling-in the grating.

Description

technical field [0001] The invention relates to the field of display technology, in particular to an optical waveguide and a display device. Background technique [0002] Augmented reality technology (Augmented Reality, AR) display device can integrate the real background environment while displaying virtual image information, and realize the organic combination of virtual and reality. field has been widely used. AR display devices are mainly head-mounted, so devices are required to be thinner and lighter to meet long-term wearing comfort. Among the various implementation schemes of AR display devices, holographic optical waveguide technology uses slab waveguide as the light propagation medium and holographic element as the optical path folding device. It has the advantages of simple structure, light weight and small size, and is the key to the next generation of AR display. technology. [0003] The technical principle of the holographic optical waveguide is as follows: t...

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Problems solved by technology

[0005] In order to solve the above-mentioned technical problems, the present invention provides an optical waveguide and a display device to solve the two requirements of the optical waveguide that cannot be satisfied at the same time: no secondary diffraction occurs at the in-coupling grating, and the expanded exit pupil at the out-coupling grating is consecutive questions

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