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: A laser projection module is disclosed, which comprises a laser source and a diffractive optical element, and has a first operating mode and a second operating mode. In the first operating mode, a laser beam from the laser source irradiates the diffractive optical element in a first incident state, and the diffractive optical element projects a first light field comprising a patterned light field. In the second operating mode, the laser beam from the laser source irradiates the diffractive optical element in a second incident state different from the first incident state, and the diffractive optical element projects a second light field comprising a uniform light field. The laser projection module with different operating modes of the present disclosure integrates function of projecting a patterned light field and that of projecting a uniform light field.

Abstract: The application discloses an optical waveguide device for image display and a display device. The optical waveguide device comprises a coupling-in grating and a coupling-out grating provided on a waveguide substrate. The coupling-out grating is used to couple, at least a portion of light propagating into it along an input direction, out of the waveguide substrate, and has a receiving end located upstream and a coupling-out end located downstream along the input direction. The receiving end is divided into a first grating area, a second grating area and a blank area between the first and second grating areas in a width direction perpendicular to the input direction. The blank area can prevent central light from being prematurely diffracted and splited by the coupling-out grating, thereby reducing the loss of light energy while ensuring effective coupling-out into an eyebox range, maximizing coupling-out efficiency, and improving the optical effect.

Abstract: The disclosure provides a diffraction optical waveguide, a design method thereof and a near-eye display device. The diffraction optical waveguide includes: a waveguide substrate; a coupling-in grating configured to couple image light into the waveguide substrate through diffraction; and a coupling-out grating configured to couple at least a part of diffracted light propagating thereinto out of the waveguide substrate through diffraction, wherein the waveguide substrate includes M layers of waveguide media, a catadioptric interface is formed between adjacent waveguide media, the diffracted light passes through the M layers of waveguide media in sequence and is split by the catadioptric interface, beams after light splitting propagate towards a coupling-out zone along different transmission paths in the M layers of waveguide media, each layer of waveguide medium has a different refractive index, a refractive index of an ith layer of waveguide medium being ni, an air refractive index being n0, and |ni?ni?1|?0.

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 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 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: 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 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: A diffractive optical waveguide is disclosed, in which a grating structure comprises a plurality of optical unit structures arranged in an array, a cross-section of an optical unit structure has a shape with two small ends and a large middle part, length L and maximum width W of the cross-section satisfy 0.2L?W?0.8L, and contour curves each are formed between an upper vertex and a left vertex, the upper vertex and a right vertex, a lower vertex and the left vertex, and the lower vertex and the right vertex, respectively. A display device comprising the same and a design and formation method for the same are also disclosed. The cross-section of the optical unit structure has a curved contour, with edges which are smooth and have very good processability. Also, the cross-section with curve contour of the optical unit structure has a very high degree of design freedom.

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: 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 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: 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.