Abstract: The present application provides a diffractive optical waveguide for optical pupil expansion and a display device. The diffractive optical waveguide for optical pupil expansion comprises a waveguide substrate; a coupling-out grating disposed on or in the waveguide substrate and configured to couple input light out of the waveguide substrate by diffraction, wherein the coupling-out grating comprises a plurality of grating lines with widths; the plurality of grating lines are spaced in a cycle of a first predetermined period along a first direction and are spaced in a cycle of a second predetermined period along a second direction; each of the grating lines comprises a plurality of periodic structures in continuous and connected arrangement. Each of the periodic structures comprises a first edge and a second edge spaced in the first direction. The first predetermined period is defined as the distance between the first edge and the second edge in the first direction.

Abstract: A diffractive optical waveguide for optical pupil expansion and a display device are provided. The diffractive optical waveguide comprises a waveguide substrate and a grating structure. The grating structure is disposed on a surface of the waveguide substrate or in the waveguide substrate and comprises a plurality of periodic structures arranged at intervals along a first direction and arranged at intervals along a second direction. The second direction is different from the first direction. A first distance between the centers of adjacent periodic structures in the first direction is smaller than a second distance between the centers of adjacent periodic structures in the second direction. The grating structure is equivalent to a one-dimensional grating with a grating vector in a vertical direction of the first direction, and the vertical direction is parallel to a plane where the grating structure is located.

Abstract: An optical waveguide device is disclosed, in which an input section comprises a first waveguide substrate and a first relief grating formed on a surface thereof, and refractive indices n1, n2 of the first relief grating and the first waveguide substrate satisfy n2<n1, such that a first maximum average number of reflections that a light beam within a predetermined FOV range is subjected to on the surface after diffraction of the predetermined order before leaving a region where the first relief grating lies, is N, and N?2, wherein when N?1, N?M?0.25; when 1<N?1.5, N?M?0.5; and when 1.5<N?2, N?M?0.75, wherein M is a second maximum average number of reflections assuming the first waveguide substrate has the same refractive index as the first relief grating.

Abstract: A diffraction optical waveguide is disclosed, which comprises a grating structure formed on a waveguide substrate. The grating structure comprises a plurality of optical unit structures arranged in an array along a plane; the optical unit structure has a first end and a second end in a first direction parallel to the plane, a distance between the two ends along the first direction is a length L of the optical unit structure; it has a maximum width W perpendicular to the first direction in a predetermined section along the first direction, where 0.3L?W?0.7L, and a central position of the predetermined section is at a predetermined distance d from the first end in the first direction, where d<0.5L; and a width gradually decreases from the predetermined section to both ends, so that a centroid of a cross-section of the optical unit structure is closer to the first end.

Abstract: The disclosure provides a design method of a coupling-out grating and the design method including: calculating a diffraction coupling-in angle, at which a light beam is diffracted and coupled into the optical waveguide body through the coupling-in grating, according to an angle at which the light beam is incident to the coupling-in grating, a wavelength of the light beam and a grating period of the coupling-in grating; calculating a distance between two adjacent coupling-out positions of the light beam; calculating a brightness difference rate of the light beam after being coupled out multiple times through the coupling-out grating according to the maximum diffraction efficiency of the coupling-out grating; and calculating the number of partitions of the coupling-out grating according to a length of the coupling-out grating, a sensitivity of a human eye to the light beam, the brightness difference rate, and the distance between the two adjacent coupling-out positions.

Abstract: A diffractive optical waveguide and a display device having the same are disclosed, which waveguide comprises a grating structure formed on a surface of a waveguide substrate. The grating structure comprises a plurality of grating lines arranged in a plane, which extend along a first direction in the plane and are arranged at a predetermined interval in a second direction perpendicular to the first direction; at least one sidewall of each grating line has a periodic structure along the first direction; and the grating structure is configured to diffract light incident thereon at a non-zero angle with respect to the plane, out of the plane through a predetermined diffraction order. The grating structure in the diffractive optical waveguide can be used to adjust diffraction efficiency on different angles and/or diffraction orders, thereby providing a new effective and flexible means for improving angular uniformity and/or coupling-out efficiency of the waveguide.

Abstract: A diffractive optical waveguide and a display apparatus are disclosed. A coupling-out grating includes a first grating having a first, second, and third grating vectors, directions of the second and third grating vectors, being respectively towards both sides of a direction of first grating vector, form acute angles with it, a cross-section profile of an optical unit structure of the first grating has a first, second, third, and fourth vertices, a straight line passing through the first and second vertices and a straight line passing through the third and fourth vertices are perpendicular to the direction, a straight line passing through the first and fourth vertices and a straight line passing through the second and third vertices respectively form angles ?1 and ?2 having a same sign with the direction, wherein 15°?|?1|?45° and 15°?|?2?45°.

Abstract: The present application provides a diffractive optical waveguide for optical pupil expansion and a display device, comprising a waveguide substrate having a coupling-in region in which a coupling-in grating is located and a coupling-out region. A first and a second diffractive light obtained by the input light diffracted by the coupling-in grating are respectively totally reflected in the waveguide substrate and directed to a first and a second coupling-out regions. A first coupling-out grating disposed in the first coupling-out region and a second coupling-out grating disposed in the second coupling-out region both are configured to couple at least a portion of light propagating therein out of the waveguide substrate by diffraction. The first and the second coupling-out regions are respectively located at both sides of the coupling-in region. A center of the coupling-in region deviates from the center line connecting the centers of the first and the second coupling-out regions.

Abstract: A diffraction optical waveguide, a grating structure, and a display device are disclosed. An arrangement period of a grating line of the grating structure is T and the grating line has a cross-sectional profile with a narrow top and a wide bottom. The cross-sectional profile includes five feature points, which respectively have coordinates (0, 0), (L2, H2), (L3, H3), (L4, H4), (L5, 0), and satisfy: 0.2T?L2<L3<L4?L5?T; L3?0.8T; L3?L2?0.1T; L4?0.8T; 0?H2??; 0.2??H3??; 0.6??H4?1.8?; max(H2, H3)?H4; ?0.6??H3?H2?0.6?, 0.6??H3+H2?1.8?; 0.5?/T?H3/L3?2?/T, where ? is a wavelength. According to an embodiment of the present disclosure, the cross-sectional profile can be adjusted by controlling parameters of the feature points, the optical effect is improved and degrees of freedom in design and regulation are increased.

Abstract: A diffractive optical waveguide and a display device for optical pupil expansion are provided. The diffractive optical waveguide comprises a waveguide substrate; a coupling-in grating; and a coupling-out grating comprising first, second, and third coupling-out gratings that are arranged successively in a first direction. The second coupling-out grating is corresponding to a region that includes a first edge and a second edge spaced in a second direction orthogonal to the first direction. The second direction is orthogonal to the first direction. The first edge is closer to the coupling-in grating than the second edge. A first width of the first edge in the first direction is greater than a second width of the second edge in the first direction. The light output by the coupling-in grating is incident on the second coupling-out grating through the waveguide substrate, and is diffracted by the second coupling-out grating into a plurality of beam splits.

Abstract: A diffractive optical waveguide is provided, which comprises a waveguide substrate and a coupling-in grating, a coupling-out grating, and a coupling-in end light-return grating formed on the substrate, the coupling-in grating couples an input beam into the waveguide substrate and forms a first beam of light propagating toward the coupling-out grating and a second beam of light not propagating toward the coupling-out grating, the coupling-out grating couples at least a part of the light propagating therein out of the substrate, and the coupling-in end light-return grating diffracts the second beam of light so that it propagates toward the coupling-out grating. A display device having the above diffractive optical waveguide is also disclosed. By providing the coupling-in end light-return grating, optical coupling efficiency of the diffractive optical waveguide is improved, and the energy distribution uniformity of an output field of the diffractive optical waveguide is improved.

Abstract: The invention provides a method for designing a diffractive optical element, characterized in comprising: S101: obtaining a first optical field pattern on a target plane; S102: converting the first optical field pattern on the target plane into a second optical field pattern on a spherical surface; S103: compensating for missing points of the second optical field pattern on the spherical surface, and matching grayscale values, so as to obtain a corrected third optical field pattern; and S104: obtaining a phase distribution of the diffractive optical element according to the third optical field pattern. By means of the design method, the projection quality of a diffractive optical element is improved.

Abstract: 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.

Abstract: Provided is a mobile apparatus obstacle detection system (100), a mobile apparatus (10) carrying the obstacle detection system (100), and a ground-sweeping robot. The obstacle detection system (100) comprises: a structured light projection module (102) configured to project structured light onto the path of advance of the mobile apparatus (10), the structured light comprising at least one lateral detection line in the horizontal direction and at least one longitudinal detection line in the vertical direction; a camera module (103) configured to capture an image of the structured light (105); and an image processing module (104) configured to calculate, according to the image of the structured light (105), the distances and positions of obstacles (106, 107, 108) on the path of advance.

Abstract: A method for designing a phase-typed diffraction suppressing optical device (12) for a transparent display screen(11) is disclosed, which comprises: acquiring a light field complex amplitude distribution U(x2,y2,d)=A(x2,y2,d)exp(i?20(x2,y2,d)) on a plane with a distance d from the transparent display screen (12) after a plane wave is transmitted through the screen; and designing the diffraction suppressing optical device (12), so that it has a transmittance function t2 (x2,y2)=exp(i?21(x2,y2)) and satisfies ?20 (x2,y2,d)+?21 (x2,y2)=C, where C is a constant. A diffraction suppressing optical device (12) and an under-screen camera apparatus (1) comprising the same are disclosed. The phase-typed diffraction suppressing optical device (12) suppresses the diffraction effect in the under-screen camera apparatus (1) by providing phase modulation, thereby improving the quality of under-screen imaging.

Abstract: Provided is a design method for a diffractive optical element for being used for projecting an oblique line. The method comprises: determining an angle ? between an oblique line and a first direction (S101); according to the angle, determining a first cycle d1 of a diffractive optical element in the first direction and a second cycle d2 of the diffractive optical element in a second direction, wherein the first direction is perpendicular to the second direction, and the first cycle d1 and the second cycle d2 satisfy tg?=d1/d2 (S102); and obtaining a phase distribution map of the diffractive optical element according to the first cycle d1, the second cycle d2 and a target pattern with an oblique line at 45° (S103). By means of the design method, the visual effect of an optical field projected by means of a diffractive optical element can be improved.