An image light guide for conveying image bearing light comprising a substrate operable to propagate image-bearing light beams along a length thereof. An in-coupling diffractive optic is formed along the substrate and is operable to diffract a portion of image-bearing light beams from an image source into the substrate in an angularly encoded form. An out- coupling diffractive optic is formed along the substrate at least partially in a plane having an x-axis and a y-axis, and is operable to diffract a portion of the image-bearing light beams from the substrate in an angularly decoded form. The out-coupling diffractive optic comprises a first plurality of periodic structures and a second plurality of periodic structures operable to diffract a portion of the image-bearing light beams into diffractive orders. The first and second pluralities of periodic structures comprise a plurality of vertices, wherein each adjacent vertex along the x-axis is offset in the y-axis direction.

An image light guide for conveying image bearing light comprising a substrate operable to propagate image-bearing light beams along a length thereof. An in-coupling diffractive optic is formed along the substrate and is operable to diffract a portion of image-bearing light beams from an image source into the substrate in an angularly encoded form. An out- coupling diffractive optic is formed along the substrate at least partially in a plane having an x-axis and a y-axis, and is operable to diffract a portion of the image-bearing light beams from the substrate in an angularly decoded form. The out-coupling diffractive optic comprises a first plurality of periodic structures and a second plurality of periodic structures operable to diffract a portion of the image-bearing light beams into diffractive orders. The first and second pluralities of periodic structures comprise a plurality of vertices, wherein each adjacent vertex along the x-axis is offset in the y-axis direction.

A display apparatus capable of providing an expanded viewing window includes a light guide plate including an input coupler and an output coupler; and an image providing apparatus facing the input coupler to provide an image to the input coupler. The input coupler may include a plurality of sub input couplers configured to propagate the image provided from the image providing apparatus at different angles in the light guide plate.

A display apparatus capable of providing an expanded viewing window includes a light guide plate including an input coupler and an output coupler; and an image providing apparatus facing the input coupler to provide an image to the input coupler. The input coupler may include a plurality of sub input couplers configured to propagate the image provided from the image providing apparatus at different angles in the light guide plate.

Aspects of the subject disclosure are directed towards safely projecting a diffracted light pattern, such as in an infrared laser-based projection/illumination system. Non-diffracted (zero-order) light is refracted once to diffuse (defocus) the non-diffracted light to an eye safe level. Diffracted (non-zero-order) light is aberrated twice, e.g., once as part of diffraction by a diffracting optical element encoded with a Fresnel lens (which does not aberrate the non-diffracted light), and another time to cancel out the other aberration; the two aberrations may occur in either order. Various alternatives include upstream and downstream positioning of the diffracting optical element relative to a refractive optical element, and/or refraction via positive and negative lenses.

Aspects of the subject disclosure are directed towards safely projecting a diffracted light pattern, such as in an infrared laser-based projection/illumination system. Non-diffracted (zero-order) light is refracted once to diffuse (defocus) the non-diffracted light to an eye safe level. Diffracted (non-zero-order) light is aberrated twice, e.g., once as part of diffraction by a diffracting optical element encoded with a Fresnel lens (which does not aberrate the non-diffracted light), and another time to cancel out the other aberration; the two aberrations may occur in either order. Various alternatives include upstream and downstream positioning of the diffracting optical element relative to a refractive optical element, and/or refraction via positive and negative lenses.

A waveguide assembly is provided. The waveguide assembly includes a pair of pupil-replicating waveguides. The first pupil-replicating waveguide is configured for receiving an input beam of image light and providing an intermediate beam comprising multiple offset portions of the input beam. The second pupil-replicating waveguide is configured for receiving the intermediate beam from the first pupil-replicating waveguide and providing an output beam comprising multiple offset portions of the intermediate beam. The input beam may be expanded by the waveguide assembly in such a manner that pupil gaps are reduced or eliminated.

A waveguide assembly is provided. The waveguide assembly includes a pair of pupil-replicating waveguides. The first pupil-replicating waveguide is configured for receiving an input beam of image light and providing an intermediate beam comprising multiple offset portions of the input beam. The second pupil-replicating waveguide is configured for receiving the intermediate beam from the first pupil-replicating waveguide and providing an output beam comprising multiple offset portions of the intermediate beam. The input beam may be expanded by the waveguide assembly in such a manner that pupil gaps are reduced or eliminated.

The present application provides a diffractive optical waveguide for optical pupil expansion and a display device. The diffractive optical waveguide comprises a waveguide substrate having a coupling-in region and a coupling-out region that includes a first coupling-out region, a second coupling-out region, and a transitional region; a coupling-in grating; and a coupling-out grating. The coupling-out grating comprises first and second coupling-out gratings and a plurality of transitional coupling-out grating. The first and second coupling-out gratings are arranged in a first direction. The transitional region comprises a plurality of sub-regions each correspondingly provided with one of transitional coupling-out gratings. The transitional coupling-out grating has a first, a second, and a third vector direction. The third vector direction is parallel to the vector direction of the first coupling-out grating. The first vector direction forms a first included angle with the third vector direction, and the second vector direction forms a second included angle with the third vector direction. The first included angle corresponding to the one, in two neighboring transitional coupling-out gratings, closer to the second coupling-out grating is greater than the first included angle corresponding to the farther one; and/or, the second included angle corresponding to the one closer to the second coupling-out grating is greater than the second included angle corresponding to the farther one.

The present application provides a diffractive optical waveguide for optical pupil expansion and a display device. The diffractive optical waveguide comprises a waveguide substrate having a coupling-in region and a coupling-out region that includes a first coupling-out region, a second coupling-out region, and a transitional region; a coupling-in grating; and a coupling-out grating. The coupling-out grating comprises first and second coupling-out gratings and a plurality of transitional coupling-out grating. The first and second coupling-out gratings are arranged in a first direction. The transitional region comprises a plurality of sub-regions each correspondingly provided with one of transitional coupling-out gratings. The transitional coupling-out grating has a first, a second, and a third vector direction. The third vector direction is parallel to the vector direction of the first coupling-out grating. The first vector direction forms a first included angle with the third vector direction, and the second vector direction forms a second included angle with the third vector direction. The first included angle corresponding to the one, in two neighboring transitional coupling-out gratings, closer to the second coupling-out grating is greater than the first included angle corresponding to the farther one; and/or, the second included angle corresponding to the one closer to the second coupling-out grating is greater than the second included angle corresponding to the farther one.