CN117608021A - Light leakage prevention diffraction optical waveguide device and display equipment with same - Google Patents

Abstract

The application discloses leak protection light diffraction optical waveguide device, including waveguide substrate and the coupling grating of formation on the substrate, the coupling grating includes the two-dimensional grating structure of formation on a substrate surface of waveguide substrate, and the two-dimensional grating structure includes the structure surface that stretches in the direction parallel to substrate surface and along this structure surface a plurality of optical unit structures of arranging into the array, and the optical unit structure is columnar structure and is formed with terminal surface and the lateral wall of connection between terminal surface and structure surface, and wherein, the terminal surface is inclined with respect to the substrate surface. In the light leakage prevention diffraction optical waveguide device, the modulation on the depth/height direction of the two-dimensional grating is formed, so that light leakage on the visual field side is restrained, and the coupling-out efficiency of the diffraction optical waveguide to the observation window is improved.

Description

Light leakage prevention diffraction optical waveguide device and display equipment with same

Technical Field

The present invention relates to a display technology based on a diffraction optical waveguide, and more particularly, to a diffraction optical waveguide device for preventing light leakage and a display apparatus having the diffraction optical waveguide device for preventing light leakage.

Background

Along with the development of scientific technology, the AR (Augmented Reality ) display technology is moving to the public as a very intelligent and portable display technology, and is mainly characterized in that virtual pictures are superimposed on real scenes, so that people can watch real scenes while watching the virtual pictures. Diffractive optical waveguide devices have been widely used in AR displays. The diffraction optical waveguide has the advantages of light weight, strong pupil expansion capability, easy mass production and the like, and becomes a core device of the AR display equipment.

However, the conventional diffractive optical waveguide device for display has some problems such as large light leakage on the viewing side of the device. Fig. 1 schematically shows a state of a diffractive optical waveguide device when used for display, wherein: the diffractive optical waveguide device comprises a substrate S and a coupling-in grating 1 and a coupling-out grating 2 formed on the substrate, the coupling-in grating 1 coupling in an input light beam carrying image information from an optical machine LE into the waveguide substrate S and propagating it towards the coupling-out grating 2, the coupling-out grating 2 being used for coupling out light (see solid arrow in fig. 1) from the waveguide substrate to a coupling-out side (side on which the eye E is shown in fig. 1). However, as indicated by the dashed arrow in fig. 1, some light still exits toward the viewing side WS opposite to the coupling-out side, resulting in the above-described light leakage problem. Such light leakage causes a large energy loss, and also leaks privacy, and may affect surrounding persons.

Accordingly, it is desirable to provide a diffractive optical waveguide device with improved light leakage prevention.

Disclosure of Invention

The invention aims to provide a diffraction optical waveguide device and a display device with the diffraction optical waveguide device, which effectively reduces light leakage of the diffraction optical waveguide device on the visual field side.

According to one aspect of the present invention, there is provided a leak-proof diffraction optical waveguide device comprising a waveguide substrate and an in-grating and an out-grating formed on the waveguide substrate, wherein

The coupling-in grating is configured to couple an input light beam from outside the waveguide substrate into the waveguide substrate by diffraction and to be propagated to the coupling-out grating by total reflection;

the coupling-out grating includes a two-dimensional grating structure formed on a substrate surface of the waveguide substrate, the two-dimensional grating structure including a structure surface extending in a direction parallel to the substrate surface and a plurality of optical unit structures arranged in an array along the structure surface for expanding light propagating therein by diffraction in a plane parallel to the substrate surface while being coupled out from the waveguide substrate, wherein the optical unit structures are columnar structures and are formed with an end face and a side wall connected between the end face and the structure surface, wherein the end face is inclined with respect to the substrate surface.

Advantageously, the tilt pitch angle of the end faces of the plurality of optical cell structures of the two-dimensional grating structure with respect to the substrate surface is in the range of 5 ° to 25 °. Preferably, the pitch angle is in the range of 10 ° to 20 °.

According to various embodiments of the present invention, the columnar structure may be a columnar protrusion structure or a columnar recess structure, and the end surface is a top surface of the protrusion structure or a bottom surface of the recess structure.

Advantageously, the side wall is perpendicular to the substrate surface.

Advantageously, the end face comprises at least one inclined surface inclined with respect to the substrate surface, each inclined surface having a respective inclined orientation, the inclined orientation being a direction perpendicular to the inclined surface and directed by a projection of a ray directed away from a side of the waveguide substrate onto the substrate surface; and is also provided with

The two-dimensional grating structure includes a first region, and end faces of a plurality of the optical unit structures in the first region include inclined faces having the same first inclination orientation.

Advantageously, the end faces of the plurality of optical units in the first region are inclined in the same direction relative to the substrate surface.

Advantageously, the end face of at least one of the optical unit structures in the first region comprises a plurality of inclined faces, and the plurality of inclined faces each have the first inclined orientation.

Advantageously, the array comprises a plurality of rows perpendicular to a first direction formed by the arrangement of the plurality of optical cell structures, the plurality of rows being arranged at predetermined intervals in the first direction, the optical cell structures being arranged at a period P in the rows, and the optical cell structures in two adjacent rows of the plurality of rows having a misalignment s=p/n in a direction perpendicular to the first direction, wherein 1<n +.5, preferably n=2; and the first oblique orientation is parallel to the first direction.

Advantageously, the out-coupling grating is a reflective out-coupling grating for out-coupling at least a part of the light propagating therein in the in-coupling direction by total reflection within the waveguide substrate by diffraction from the waveguide substrate towards the opposite side of the side where the out-coupling grating is located, and the first oblique orientation is the same as the in-coupling direction; or alternatively

The out-coupling grating is a transmissive out-coupling grating for out-coupling at least a portion of light propagating therein in the in-coupling direction by total reflection within the waveguide substrate by diffraction from the waveguide substrate towards a side where the out-coupling grating is located, and the first tilted orientation is opposite to the in-coupling direction.

According to some embodiments of the invention, the two-dimensional grating structure further comprises a second region, the end faces of the plurality of optical cell structures in the second region comprising inclined faces having a same second inclined orientation, the second inclined orientation being different from the first inclined orientation.

According to some embodiments of the invention, the two-dimensional grating structure may further comprise a third region located between the first region and the second region, the end faces of the plurality of optical unit structures in the third region comprising inclined faces having the same third inclination orientation, the third inclination orientation being intermediate the first inclination orientation and the second inclination orientation.

Alternatively or additionally, the two-dimensional grating structure may further comprise a third region located between the first region and the second region, the end face of each of the optical unit structures in the third region comprising both a bevel having a first oblique orientation and a bevel having a second oblique orientation.

Advantageously, the edge of the end face has a first point furthest from the substrate surface and a second point closest to the substrate surface, and the maximum distance Hi between points on an intersection line of a virtual plane passing through the first point and the second point and perpendicular to the substrate surface and the end face and connecting the first point and the second point in a height direction perpendicular to the substrate surface is: hi is less than or equal to H/3, and H is the distance between the first point and the second point in the height direction.

Advantageously, the edge of the end face has a first point furthest from the substrate surface and a second point closest to the substrate surface, the distance from the substrate surface at each point gradually decreasing or leveling from the first point to the second point on an intersection of a virtual plane passing through the first point and the second point and perpendicular to the substrate surface and the end face.

Advantageously, each of the inclined planes of the end faces of the plurality of optical unit structures of the two-dimensional grating structure has an inclination pitch angle in the range of 5 ° to 30 ° with respect to the substrate surface.

Advantageously, the projected shape of the optical unit structure on the substrate surface is an elongated shape elongated in the first direction.

According to various embodiments of the invention, the elongated shape may be diamond, curvilinear diamond, double diamond, curvilinear double diamond, or oval.

The projected shape of the optical unit structure on the substrate surface may be symmetrical or asymmetrical with respect to the first direction.

According to another aspect of the present invention, there is also provided a display device including the light leakage preventing diffractive optical waveguide as described above.

According to some embodiments of the invention, the display device is a near-eye display device and comprises a lens and a frame for holding the lens close to the eye, the lens comprising the light-leak-proof diffractive optical waveguide.

Advantageously, the display device is an augmented reality display device or a virtual reality display device.

According to the embodiment of the invention, in the coupling-out grating of the light leakage prevention diffraction optical waveguide device, the grating unit structure of the two-dimensional grating structure is configured to have the end face inclined relative to the surface of the waveguide substrate, so that the modulation on the depth/height direction of the two-dimensional grating is formed, and the light leakage on the visual field side is favorably inhibited and the coupling-out efficiency of the diffraction optical wave guiding observation window is improved.

Drawings

Other features, objects and advantages of the present invention will become more apparent upon reading of the detailed description of non-limiting embodiments, made with reference to the following drawings in which:

FIG. 1 schematically illustrates the problem of light leakage of a diffractive optical waveguide device when displayed;

FIG. 2 is a schematic plan view of a light leakage preventing diffractive optical waveguide device according to a first embodiment of the present invention;

fig. 3 is a schematic view of one example of an optical unit structure that can be used in the light leakage preventing diffractive optical waveguide device according to an embodiment of the present invention;

FIG. 4 is a schematic view of a partial cross section taken along the x-z plane of a different example of a light leakage preventing diffractive optical waveguide device according to a first embodiment of the present invention, wherein the optical unit structure of the two-dimensional grating structure of the coupling-out grating is a columnar bump structure, and the top surface of the bump structure has a tilt azimuth angle of 0 °;

FIG. 5 is a schematic view of a partial cross section taken along the x-z plane of a different example of a light leakage preventing diffractive optical waveguide device according to a first embodiment of the present invention, wherein the optical unit structure of the two-dimensional grating structure of the coupling-out grating is a columnar concave hole structure, and the bottom surface of the concave hole structure has a tilt azimuth angle of 0 °;

FIG. 6 is a schematic partial cross-sectional view taken along the x-z plane of a different example of a light leakage preventing diffractive optical waveguide device according to a first embodiment of the present invention, in which an end face of an optical unit structure of a two-dimensional grating structure of a coupling-out grating has a tilt azimuth angle of 180 °;

FIG. 7 schematically illustrates different examples of optical cell structures in which the end face of the optical cell structure includes one or more beveled surfaces;

FIG. 8 schematically illustrates an example of an array of optical cell structures of a two-dimensional grating structure coupling out a grating in a light leak-proof diffractive optical waveguide device according to an embodiment of the present invention;

FIG. 9 shows a schematic cross-sectional view taken along the x-z plane and a related oblique orientation view of the three optical cell structures employed in data example 1;

FIG. 10 is a graph showing the zero order reflection efficiency as a function of angle of view/angle of incidence for a two-dimensional grating structure employing different optical cell structures in data example 1;

FIG. 11 is a graph showing the coupling-out efficiency of two-dimensional grating structures using different optical unit structures as a function of angle of view/angle of incidence in data example 1;

FIG. 12 shows a schematic cross-sectional view taken along the x-z plane and a related oblique orientation view of the three optical cell structures employed in data example 2;

FIG. 13 is a graph showing the coupling-out efficiency of two-dimensional grating structures using different optical unit structures as a function of angle of view/angle of incidence in data example 2;

FIG. 14 is a graph showing the reflection outcoupling efficiency as a function of angle of view/angle of incidence after two-sided beam splitting using a two-dimensional grating structure with different tilt-pitch angle optical unit structures in data example 3;

FIG. 15 is a graph showing the reflection outcoupling efficiency as a function of angle of view/angle of incidence for a two-dimensional grating structure employing optical unit structures with different tilt-pitch angles in data example 3;

FIG. 16 is a schematic plan view of a light leakage preventing diffractive optical waveguide device according to a second embodiment of the present invention, in which a two-dimensional grating structure of a coupling-out grating is shown to include a first region and a second region;

FIG. 17 is a schematic plan view of a light leakage preventing diffractive optical waveguide device according to a third embodiment of the present invention, in which a two-dimensional grating structure of a coupling-out grating is shown including first to third regions;

fig. 18 is a schematic plan view of a light leakage preventing diffractive optical waveguide device according to a modification of the third embodiment of the present invention, in which a two-dimensional grating structure of an out-coupling grating is shown including first to third regions, and the in-coupling grating is disposed offset with respect to the out-coupling grating.

Detailed Description

The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. For convenience of description, only parts related to the invention are shown in the drawings. It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other.

Fig. 2 shows an example of the light leakage preventing diffractive optical waveguide device 100 according to the first embodiment of the present invention in a plan view. As shown in fig. 2, the light leakage preventing diffraction optical waveguide device 100 according to the first embodiment of the present invention includes a waveguide substrate 100a and an in-coupling grating 110 and an out-coupling grating 120 formed on the waveguide substrate 100 a.

The coupling-in grating 110 is configured to couple an input light beam from outside the waveguide substrate 100a into the waveguide substrate 100a by diffraction and to be propagated to the coupling-out grating 120 by total reflection. IN the example shown IN fig. 2, the direction of light propagating from the incoupling grating 110 to the incoupling grating 120 (i.e. the incoupling direction) is shown by the arrow IN fig. 2. In the context of the present application, for clarity and brevity, the orientation of the coupling-in direction in an x-y plane parallel to the substrate surface 101 is denoted by the azimuth angle αin, and the azimuth angle αin is determined to be 0 ° as a reference for the azimuth angle in the x-y plane, as shown in the schematic diagram of the orientation in the left-hand dashed box in fig. 2.

The out-coupling grating 120 comprises a two-dimensional grating structure 120A formed on a substrate surface 101 of the waveguide substrate 100A. For ease of reference, a schematic enlarged view of the two-dimensional grating structure 120A is given in the right-hand dashed box in fig. 2. As shown, the two-dimensional grating structure 120A includes a structure surface 11 (which may be referred to as surface 11 shown in fig. 4, 5 and 6) extending in a direction parallel to the substrate surface 101 (including x-direction and y-direction) and a plurality of optical unit structures 10 arranged in an array along the structure surface 11 for expanding light propagating therein by diffraction in an x-y plane parallel to the substrate surface 101 and simultaneously coupling out from the waveguide substrate 100A.

Fig. 3 schematically shows one example of an optical unit structure that can be used for the light leakage preventing diffractive optical waveguide device according to the embodiment of the present invention. As shown in fig. 3, the optical unit structure 10 is a columnar structure and is formed with an end face 10a and a side wall 10b connected between the end face 10a and the structure surface 11, and it can be seen that the end face 10a is inclined with respect to the x-y plane so as to be inclined with respect to the substrate surface 101.

The scale units in the x-direction, y-direction, and direction perpendicular to the x-y plane (i.e., z-direction) shown in fig. 3 are nanometers, however, it should be understood that the dimensions shown in fig. 3 are exemplary and illustrative only and are not intended to limit the scope of the present invention in any way.

In the example shown in fig. 3, the optical unit structure 10 is shown as having a columnar convex structure, but the present invention is not limited thereto. In a different example, in the light leakage preventing diffractive optical waveguide device according to the embodiment of the present invention, the optical unit structure 10 may be a columnar concave hole structure, or may be a combination of a columnar convex structure and a columnar concave hole structure. In this application, the end face 10a of the optical unit structure 10 may be the top face of the columnar bump structure and/or the bottom face of the columnar concave hole structure.

When the optical unit structure 10 is a columnar concave hole structure, the end face 10a of the optical unit structure 10 is the bottom face of the columnar concave hole structure, and the side wall 10b is the surface connected between the bottom face and the structural surface 11; also according to an embodiment of the invention, the bottom surface 10a is inclined with respect to the substrate surface 101.

According to the light leakage prevention diffraction optical waveguide device, in the two-dimensional grating structure of the coupling-out grating, the grating unit structure is configured to have the end face inclined relative to the surface of the waveguide substrate, so that the modulation on the depth/height direction of the two-dimensional grating is formed, light leakage on the visual field side is favorably inhibited, and the coupling-out efficiency of the diffraction optical wave guiding observation window is improved.

Advantageously, in the light leakage preventing diffractive optical waveguide device according to the embodiment of the present invention, the axial direction of the columnar structure of the optical unit structure 10 may be perpendicular to the substrate surface 101. In particular, in some implementations, the sidewalls 10b of the optical cell structure 10 may be perpendicular to the substrate surface 101. This is advantageous in simplifying the design and processing of the optical cell structure 10. Here, "perpendicular to" is intended to cover a slight deviation of the axial direction of the sidewall or the columnar structure as a whole from the normal direction of the substrate surface 101 due to the limitation of the processing process.

IN the example shown IN fig. 2 and 3, the tilt orientation of the end face 10a of the optical unit structure 10 with respect to the substrate surface 101 is represented by a tilt azimuth angle α, α=180°, i.e., the tilt orientation of the end face 10a is opposite to the coupling-IN direction IN. As will be described in more detail below with reference to the different examples shown in the drawings, the "oblique orientation" of the end faces of the optical unit structures or of the inclined planes contained therein is referred to in this application as: the direction in which the projection of the ray perpendicular to the end face or bevel and pointing to the side remote from the waveguide substrate onto the plane of the substrate surface is directed.

It should be understood that the tilt azimuth angle α shown in fig. 2 and 3 is exemplary only and not limiting. IN different embodiments of the invention, the inclination azimuth angle α may be designed and constructed with a different relative relation to the azimuth angle αin of the coupling-IN direction IN, for example as the same as the azimuth angle αin or inclined at a different angle with respect to the latter, depending on the application requirements.

Next, several types of examples of the light leakage preventing diffractive optical waveguide device according to the first embodiment of the present invention are described with reference to fig. 4 to 6.

Fig. 4 is a schematic view of a partial cross section taken along an x-z plane of a different example of a light leakage preventing diffractive optical waveguide device according to a first embodiment of the present invention, in which an optical unit structure of a two-dimensional grating structure of an out-coupling grating is a columnar bump structure, and a top surface of the bump structure has a tilt azimuth angle of 0 °.

Specifically, in the example shown in fig. 4, the substrate surface 101 of the waveguide substrate 100a coincides with the structure surface 11 of the two-dimensional grating structure. In other examples, a dielectric structure (e.g., composed of the same material as the optical unit structure) may be formed between the plurality of optical unit structures 10 and the substrate surface 101 of the waveguide substrate 100a, the surface of the dielectric structure being the structure surface 11 constituting the two-dimensional grating structure.

As shown in graphs (a) and (b) of fig. 4, the optical unit structure 10 as a columnar bump includes an end face 10a (top face of the columnar bump) and a side wall 10b formed between the end face 10a and the structure surface 11, and a projection direction of a ray N perpendicular to the end face 10a and directed to a side away from the waveguide substrate 100a on the substrate surface 101 coincides with the coupling-in direction (direction from left to right in the graph of fig. 4), that is, an inclination azimuth angle α of the end face 10a with respect to the substrate surface 101 is 0 °.

Figure 4, graph (a), shows a diffractive optical waveguide device comprising a transmissive outcoupling grating, wherein light propagating in the waveguide substrate 100a by total reflection to the outcoupling grating/optical unit structure 10 is outcoupled from the waveguide substrate 100a mainly in a manner of being transmitted through the outcoupling grating. That is, the coupling-out grating is for coupling out at least a part of light propagating therein in the coupling-in direction by total reflection within the waveguide substrate from the waveguide substrate by diffraction, and the coupling-out side of the diffractive optical waveguide device is located on the side (upper side shown in the figure (a)) where the coupling-out grating/optical unit structure 10 is located.

Graph (b) of fig. 4 shows a diffractive optical waveguide device comprising a reflective outcoupling grating, wherein light propagating in the waveguide substrate 100a to the outcoupling grating/optical unit structure 10 by total reflection is outcoupled from the waveguide substrate 100a mainly in such a way that it is reflected at the outcoupling grating, i.e. the outcoupling side of the diffractive optical waveguide device is located on the opposite side of the outcoupling grating/optical unit structure 10 (lower side shown in graph (b)).

For visual purposes, graph (c) of fig. 4 shows the tilt/azimuth angle of the end face 10a of the optical unit structure 10 in the example shown in graphs (a) and (b).

Fig. 5 is a schematic partial cross-sectional view taken along the x-z plane of another example of a light leakage preventing diffractive optical waveguide device according to a first embodiment of the present invention, in which an optical unit structure of a two-dimensional grating structure of an out-coupling grating is a columnar concave hole structure, and a bottom surface of the concave hole structure has a tilt azimuth angle of 0 °.

Specifically, in the example shown in fig. 5, the two-dimensional grating structure includes a dielectric layer M formed on the substrate surface 101 of the waveguide substrate 100a and an optical unit structure 10 of a columnar concave hole structure formed in the dielectric layer M; in this case the upper surface of the dielectric layer M constitutes the structured surface 11 of the two-dimensional grating structure. In other examples, the plurality of optical cell structures 10 may be dimple structures (e.g., made by an etching process) formed directly on the substrate surface 101 of the waveguide substrate 100 a; in this case the substrate surface 101 constitutes the structured surface 11 of the two-dimensional grating structure.

As shown in graphs (a) and (b) of fig. 5, the optical unit structure 10 as a columnar concave hole includes an end face 10a (bottom face of the columnar concave hole) and a side wall 10b formed between the end face 10a and the structure surface 11, and a projection direction of a ray N perpendicular to the end face 10a and directed to a side away from the waveguide substrate 100a on the substrate surface 101 coincides with the coupling-in direction (direction from left to right in the graph of fig. 5), that is, an inclination azimuth angle α of the end face 10a with respect to the substrate surface 101 is 0 °.

Similar to the one shown in fig. 4, the graphs (a) and (b) of fig. 5 are respectively a diffractive optical waveguide device including a transmissive coupling-out grating and a diffractive optical waveguide device including a reflective coupling-out grating, which are not described here again.

Further, graph (c) of fig. 5 shows the tilt azimuth/azimuth of the end face 10a of the optical unit structure 10 in the example shown in graphs (a) and (b).

Fig. 6 is a schematic partial cross-sectional view taken along the x-z plane of still another example of a light leakage preventing diffractive optical waveguide device according to a first embodiment of the present invention, in which an end face of an optical unit structure of a two-dimensional grating structure of a coupling-out grating has a tilt azimuth angle of 180 °.

In the example shown in the graph (a) of fig. 6, the optical unit structure 10 is a columnar bump structure, and in the example shown in the graph (b), the optical unit structure 10 is a columnar concave hole structure; in the example shown in the figures (a) and (b), the projection directions of the rays N perpendicular to the end face 10a of the optical cell structure 10 and directed to the side away from the waveguide substrate 100a on the substrate surface 101 are both opposite to the coupling-in direction (the left-to-right direction in the drawing plane of fig. 6), i.e., the inclination azimuth angle α of the end face 10a with respect to the substrate surface 101 is 180 °. Graph (c) of fig. 6 shows the tilt/azimuth of the end face 10a in the example shown in graphs (a) and (b).

Although not specifically shown in the drawings, it will be appreciated by those skilled in the art based on the foregoing that the outcoupling grating shown in fig. 6 (a) and (b) may be used as a transmissive outcoupling grating or a reflective outcoupling grating.

Next, different examples of optical unit structures that can be used for the light leakage preventing diffractive optical waveguide device according to the embodiment of the present invention will be described with reference to fig. 7, in which the end face of the optical unit structure includes one or more inclined surfaces. Fig. 7 schematically shows a cross-section of a different optical unit structure along a vertical plane (a plane containing the z-axis) in which the azimuth angle of inclination lies.

For illustrative purposes only, the optical cell structures shown in fig. 7 are all columnar bump structures, although the invention is not limited in this respect. That is, in other examples according to the present invention, the optical unit structure in which the end face includes one or more inclined surfaces as shown in fig. 7 may also be implemented as a columnar concave hole structure.

In fig. 7, the end surfaces of the optical unit structures shown in the patterns (a) and (a') are integrally formed as a slope inclined with respect to the substrate surface; the optical unit structure shown in the pattern (a') is different from the structure shown in the pattern (a) in that the end face of the former partially intersects with the structure surface (see fig. 4 to 6 and the related description) so that the side wall of the optical unit structure is formed only on a part of the optical unit structure in the circumferential direction. It should be understood that the present invention is intended to cover the case where the side wall is formed only on a part of the optical unit structure in the circumferential direction.

Further, as shown in the graph (a) of fig. 7, an angle formed by the end faces of the optical unit structure as a whole with respect to the substrate surface is denoted herein as a pitch angle θ. Preferably, the pitch angle θ is in the range of 5 ° to 25 °; more preferably, the pitch angle θ is in the range of 10 ° to 20 °.

Graphs (b), (c) and (d) of fig. 7 show that the end face of the optical cell structure may include more than one chamfer. Different slopes in the optical unit structure may have the same tilt/azimuth angle. These inclined planes may have different pitch angles θ with respect to the substrate surface _i . Preferably, the pitch angle of inclination of each inclined plane with respect to the substrate surface is in the range of 5 ° to 30 °.

In the example shown in graphs (b), (c) and (d) of fig. 7, the edge of the end face has a first point P1 furthest from the substrate surface and a second point P2 closest to the substrate surface, and the line connecting the first point P1 and the second point P2 (shown by a broken line in the figure) forms an angle with the substrate surface (a plane parallel to the substrate surface is schematically shown by a center line in the figure); in this application, the angle is equivalent to the pitch angle of the end face relative to the substrate surface. Preferably, the included angle is in the range of 5 ° to 25 °; more preferably, the pitch angle θ is in the range of 10 ° to 20 °.

Preferably, the maximum distance Hi between each point on the intersection line of the virtual plane passing through the first point P1 and the second point P2 and perpendicular to the substrate surface and the end face in the height direction perpendicular to the substrate surface satisfies: hi.ltoreq.H/3, H being the distance between the first point P1 and the second point P2 in the height direction (z direction).

Further, as shown in graphs (b), (c) and (d) of fig. 7, on an intersection line of a virtual plane passing through the first point P1 and the second point P2 and perpendicular to the substrate surface and the end face, the distances of the respective points from the substrate surface gradually decrease or become flat from the first point P1 and the second point P2.

Patterns (b '), (c ') and (d ') of fig. 7 show optical unit structures similar to those shown in patterns (b), (c) and (d), in which the end face includes an inclined surface arranged only in the difference: the end faces of the optical cell structures shown in figures (b '), (c ') and (d ') further comprise a plane 10a-1, the points in the plane 10a-1 having the greatest distance with respect to the surface of the structure (see fig. 2, 4 and 5). The design of the end face 10a to include such a flat face 10a-1 may be advantageous in reducing the difficulty of processing the end face 10 a; or in other cases such a plane 10a-1 is formed in the end face 10a due to limitations of the machining process.

In an advantageous implementation, the end face of at least one optical cell structure in at least one region of the two-dimensional grating structure comprises a plurality of inclined planes, and the plurality of inclined planes each have the same tilt/azimuth angle.

Fig. 8 schematically illustrates an example of an array of optical cell structures of a two-dimensional grating structure coupling out a grating in a light leakage preventing diffractive optical waveguide device according to an embodiment of the present invention. As shown in a graph (a) in fig. 8, the optical cell structure array of the two-dimensional grating structure 120A includes a plurality of rows perpendicular to a first direction (for example, x-direction) formed by arranging a plurality of optical cell structures 10, the plurality of rows are arranged at a predetermined interval D in the first direction, the optical cell structures 10 are arranged at a period P in each row, and the optical cell structures 10 in two adjacent rows among the plurality of rows have a misalignment s=p/n in a direction perpendicular to the first direction (for example, y-direction), wherein 1<n +.5, preferably n=2, s=p/2, as shown in fig. 8. According to the present embodiment, it is preferable that the oblique orientation of the end face of the optical unit structure in the two-dimensional grating structure 120A is parallel to the first direction.

Further, as shown in fig. 8, the projected shape of the optical unit structure 10 on the substrate surface (equivalent to the projected shape in the x-y plane) is a longitudinal shape elongated in the first direction. Wherein the optical unit structure 10 has a rhombic projected shape in the example shown in graph (a) of fig. 8, the projected shapes of the curved rhombuses and the curved double rhombuses are further shown in graphs (b) and (c). "double diamond" refers to an outer contoured shape formed by two diamond shapes of identical shape and orientation that partially overlap in their lengthwise direction. For another example, in other examples, the elongated projected shape of the optical cell structure may also be elliptical/oval, or may be "pine nut" shaped as shown in fig. 2.

It should be understood that although the projected shape of the optical cell structure 10 on the substrate surface is shown as being symmetrical with respect to the first direction, the invention is not limited in this respect and such projected shape may also be asymmetrical with respect to the first direction.

Referring back to fig. 2, an embodiment of a leak-proof diffractive optical waveguide device 100 according to the present invention is shown, wherein the outcoupling grating 120 comprises a two-dimensional grating structure 120A. According to the first embodiment, the end surfaces 10A of the plurality of optical unit structures 10 in the two-dimensional grating structure 120A include inclined surfaces having the same inclination/azimuth angle.

Advantageously, the end faces 10A of the plurality of optical units 10 in the two-dimensional grating structure 120A may be inclined in the same direction with respect to the substrate surface. Here, "tilting in the same direction" means that the tilt azimuth angle and the tilt pitch angle are the same. Such a configuration facilitates the fabrication of the diffractive optical waveguide device, thereby contributing to improved yields and reduced costs.

Advantageously, the out-coupling grating 120 is used to couple out at least a portion of the light propagating therein by total reflection IN the coupling-IN direction IN within the waveguide substrate 100a from the waveguide substrate 100a by diffraction, and the above-described same oblique orientation of the end faces 10a of the plurality of optical unit structures 10 may be the same as the coupling-IN direction IN.

Furthermore, in some implementations, it may be advantageous for the out-coupling grating 120 to be configured as a reflective out-coupling grating. By "reflective outcoupling grating" is meant that the outcoupling grating outcouples light from the waveguide substrate towards the opposite side of the side where the outcoupling grating is located.

Technical effects of the light leakage preventing diffractive optical waveguide device according to the embodiment of the present invention will be described below by way of data.

(data example 1)

In data example 1, the reflective outcoupling efficiency and the transmissive outcoupling efficiency of a two-dimensional grating structure comprising three different optical unit structures were calculated in a simulation. These two-dimensional grating structures have an array structure shown IN the graph (a) IN fig. 8, IN which the arrangement period p=4815 nm, d=420 nm, n=2, and the projection shape of the optical cell structure on the substrate surface is a diamond shape, the lengthwise direction of the diamond shape being parallel to the first direction of the array and to the coupling-IN direction IN of the light propagating to the coupling-out grating/two-dimensional grating structure.

Fig. 9 shows a schematic cross-sectional view taken along the x-z plane of the three optical cell structures employed in data example 1 and the associated tilt/azimuth diagrams. As shown in fig. 9, all three optical unit structures are columnar concave hole structures, in which: the optical unit structure 10' shown in the graph (1 a) is a non-inclined surface structure, the side length of a diamond of the projection shape of the optical unit structure on the surface of the substrate is 260nm, the vertex angle is 60 degrees, and the depth h0=65 nm; the projection shape of the optical unit structure 10A shown in the graph (1 b) on the substrate surface is the same as that of the structure 10', but has a slope 1 structure in which the inclination azimuth angle of the end face is 0 ° (see the graph (1 b'), the depth h1=25 nm of the upstream end of the end face in the coupling-in direction with respect to the structure surface 11, and the depth h2=105 nm of the downstream end with respect to the structure surface 11; the projection shape of the optical unit structure 10B shown in the figure (1 c) on the substrate surface is the same as that of the structure 10', but has a slope 2 structure in which the inclination azimuth angle of the end face is 180 ° (see the figure (1 c'), in which the upstream end of the end face in the coupling-in direction is in a depth h1=105 nm with respect to the structure surface 11 and the downstream end is in a depth h2=25 nm with respect to the structure surface 11.

In data example 1, the concave hole structures of the optical unit structures 10', 10A, and 10B were constructed to be substantially the same in volume. This means that the outcoupling efficiency of the zero-order reflection of light when it is coupled out of the grating by the two dimensions they constitute is substantially the same. Specifically, see a graph of zero order reflection efficiency as a function of angle of view/angle of incidence for a two-dimensional grating structure employing different optical unit structures in data example 1 shown in fig. 10. Under the condition that the zero-order reflection efficiency is basically the same, the coupling-out efficiency of the two-dimensional grating structure formed by three different optical unit structures in the data example 1 is simulated and compared.

The wavelength used in the simulation calculation of data example 1 was 522nm, and the incident angle of light propagating by total reflection in the waveguide substrate 100a was incident on the coupling-out grating/two-dimensional grating structure(see angle +.in FIGS. 4 and 5)>) In the range of 33 ° -50 °.

Fig. 11 shows a graph of the coupling-out efficiency as a function of angle of view/angle of incidence for a two-dimensional grating structure employing different optical cell structures in data example 1. Referring to fig. 11, the simulation result of data example 1 shows that: the transmission coupling-out efficiency and the reflection coupling-out efficiency of the two-dimensional grating structure corresponding to the optical unit structure 10' without inclined plane are relatively close, and the ratio of the reflection coupling-out average efficiency to the transmission coupling-out average efficiency at each incident angle is about 1.36; the ratio of the average reflection coupling-out efficiency to the average transmission coupling-out efficiency of the two-dimensional grating structure corresponding to the optical unit structure 10A of the inclined plane 1 structure is as high as 3.39; the ratio of the average efficiency of the reflective coupling-out to the average efficiency of the transmissive coupling-out of the two-dimensional grating structure corresponding to the optical unit structure 10B of the inclined plane 2 is about 0.51, or the ratio of the average efficiency of the transmissive coupling-out to the average efficiency of the reflective coupling-out is about 1.96.

For ease of reference, the parameters relating to the coupling-out efficiency corresponding to the above-described respective optical unit structures in data example 1 are listed below in table 1.

TABLE 1

In connection with the contents shown in fig. 11 and table 1, it can be seen that: the optical unit structure 10A of the inclined plane 1 structure greatly improves the reflective coupling-out efficiency, reduces the transmissive coupling-out efficiency, can be used as a reflective coupling-out grating to improve the efficiency of light entering the observation window, and simultaneously greatly reduces the light leakage of the diffraction optical waveguide device to the view side (opposite to the coupling-out side); the optical unit structure 10B of the inclined plane 2 is suitable for use as a transmissive outcoupling grating, which can improve the efficiency of light entering the viewing window and significantly reduce light leakage at the viewing side.

(data example 2)

In data example 2, the reflective outcoupling efficiency and the transmissive outcoupling efficiency of a two-dimensional grating structure comprising three different optical unit structures were calculated in a simulation. These two-dimensional grating structures have an array structure shown IN the graph (a) IN fig. 8, IN which the arrangement period p=4815 nm, d=420 nm, n=2, and the projection shape of the optical cell structure on the substrate surface is a diamond shape, the lengthwise direction of the diamond shape being parallel to the first direction of the array and to the coupling-IN direction IN of the light propagating to the coupling-out grating/two-dimensional grating structure.

Fig. 12 shows a schematic cross-sectional view taken along the x-z plane and a diagram of the relevant tilt orientations of the three optical cell structures employed in data example 2. As shown in fig. 12, all three optical unit structures are columnar bump structures, in which: the optical unit structure 10″ shown in the graph (2 a) is a slant-free structure, the diamond side length of the projection shape of the optical unit structure on the surface of the substrate is 220nm, the vertex angle is 60 °, and the height h0=70 nm; the projection shape of the optical unit structure 10A 'shown in the figure (2 b) on the substrate surface is the same as that of the structure 10″ but has a slope 1 structure in which the inclination azimuth angle of the end face is 0 ° (see the figure (2 b'), the depth h1=106 nm of the upstream end of the end face in the coupling-in direction with respect to the structure surface 11, and the depth h2=34 nm of the downstream end with respect to the structure surface 11; the projection shape of the optical unit structure 10B 'shown in the figure (2 c) on the substrate surface is the same as that of the structure 10″ but has a slope 2 structure in which the inclination azimuth angle of the end face is 180 ° (see the figure (2 c'), in which the upstream end of the end face in the coupling-in direction is in depth h1=34 nm with respect to the structure surface 11 and the downstream end is in depth h2=106 nm with respect to the structure surface 11.

In data example 2, the concave hole structures of the optical unit structures 10", 10A ', and 10B' were constructed to be substantially the same in volume. This means that the outcoupling efficiency of the zero-order reflection of light when it is coupled out of the grating by the two dimensions they constitute is substantially the same. Under the condition that the zero-order reflection efficiency is basically the same, the coupling-out efficiency of the two-dimensional grating structure formed by three different optical unit structures is simulated and compared in the data example 2.

The wavelength used in the simulation calculation of data example 2 was 522nm, and the incident angle of light propagating by total reflection in the waveguide substrate 100a was incident on the coupling-out grating/two-dimensional grating structureIn the range of 33 ° -50 °.

Fig. 13 shows a graph of the coupling-out efficiency as a function of angle of view/angle of incidence for a two-dimensional grating structure employing different optical cell structures in data example 2. Referring to fig. 13, the simulation result of data example 2 shows that: the ratio of the average reflective outcoupling efficiency to the average transmissive outcoupling efficiency at each angle of incidence of the two-dimensional grating structure corresponding to the non-slanted optical unit structure 10″ is about 1.32; the ratio of the reflective coupling-out average efficiency to the transmissive coupling-out average efficiency of the two-dimensional grating structure corresponding to the optical unit structure 10A' of the inclined plane 1 structure is as high as 2.13; the ratio of the average efficiency of the reflective coupling-out to the average efficiency of the transmissive coupling-out of the two-dimensional grating structure corresponding to the optical unit structure 10B' of the inclined plane 2 is about 0.83, or about 1.20.

For ease of reference, the parameters relating to the coupling-out efficiency corresponding to the above-described structures of the respective optical units in data example 2 are shown in table 2 below.

TABLE 2

/>

In combination with the disclosure shown in fig. 13 and table 2, it can be seen that the optical unit structure 10A' of the inclined plane 1 structure greatly improves the reflective coupling-out efficiency, reduces the transmissive coupling-out efficiency, and can be used as a reflective coupling-out grating to improve the efficiency of light entering the observation window, and greatly reduces the light leakage of the diffractive optical waveguide device to the view side (opposite to the coupling-out side); the optical unit structure 10B' of the inclined plane 2 structure is suitable for being used as a transmissive coupling-out grating, which can improve the efficiency of light entering the viewing window and reduce the light leakage at the viewing side.

(data example 3)

Data example 3 was designed to further examine the effect of the tilt pitch angle of the end face of the optical cell structure on the outcoupling efficiency, in particular on the re-outcoupling efficiency after splitting of the two sides of the two-dimensional grating. In data example 3, taking a case where a two-dimensional grating is used as a reflective outcoupling grating as an example, the outcoupling efficiency of the two-dimensional grating before two-sided light splitting (hereinafter referred to as "reflective outcoupling efficiency") after two-sided light splitting was examined by simulation calculation, respectively.

Specifically, data example 3 was simulated for the reflection coupling-out efficiency and the two-side spectral re-coupling-out efficiency of a two-dimensional grating structure composed of an optical unit structure (hereinafter, referred to as a structure of "no inclined plane", "inclined plane 5 °", "inclined plane 10 °", "inclined plane 15 °", "inclined plane 20 °", "inclined plane 25 °", and "inclined plane 30 °") in which the inclination azimuth angle α of the end face was 0 ° and the inclination pitch angle θ (see the angles θ shown in fig. 4, 5, and 7) was 0 °, 5 °, 10 °, 15 °, 20 °, 25 °, and 30 °, respectively. For simplicity and clarity, only an optical unit structure having a cylindrical concave hole structure with a single inclined surface at the end surface is taken as an example.

The two-dimensional grating structure IN data example 3 has an array structure shown IN graph (a) IN fig. 8, IN which the arrangement period p=4815 nm, d=420 nm, n=2, and the projected shape of the optical unit structure on the substrate surface is a diamond shape with a side length of 200nm and a vertex angle of 60 °, and the lengthwise direction of the diamond shape is parallel to the first direction of the array and parallel to the coupling-IN direction IN of light propagating to the coupling-out grating/two-dimensional grating structure. Furthermore, the average depth of the different optical unit structures was 100nm.

For two-dimensional outcoupling gratings in diffractive optical waveguide devices, the re-outcoupling efficiency after two-sided diffraction spectroscopy has a significant impact on the overall outcoupling efficiency as well as on the brightness uniformity in the field of view. Fig. 14 shows a graph of the outcoupling efficiency as a function of angle of view/angle of incidence after two-sided light splitting for the two-dimensional grating structure in data example 3. As shown in fig. 14, the simulation results show: as the tilt pitch angle theta is from 0 degrees to 15 degrees, the average re-coupling efficiency after light splitting at two sides corresponding to the two-dimensional grating structure is gradually improved; the average re-coupling efficiency after splitting light at two sides corresponding to the inclined plane 15 degrees is relatively highest on the whole; along with the inclination pitch angle theta from 15 degrees to 30 degrees, the average re-coupling efficiency of the two-dimensional grating structure after light splitting at the two sides gradually decreases, the average re-coupling efficiency of the inclined plane 25 degrees after light splitting at the two sides on the incidence angle range of the local view field is lower than that of the inclined plane without the inclined plane, and the average re-coupling efficiency of the inclined plane 30 degrees structure is reduced relative to other structures. Therefore, from the viewpoint of improving the average re-coupling efficiency after splitting light from both sides, the pitch angle θ of the end face of the optical unit structure is advantageously in the range of 5 ° to 25 °; preferably, the pitch angle θ is in the range of 5 ° to 20 °, more preferably 10 ° to 20 °.

Fig. 15 is a graph showing the reflection outcoupling efficiency as a function of angle of view/angle of incidence for a two-dimensional grating structure employing optical unit structures having different tilt-pitch angles in data example 3. As can be seen from fig. 15, the optical unit structure having the slope structure is advantageous in improving the reflection out-coupling efficiency, and as the tilt pitch angle θ is changed from 0 ° to 30 °, the reflection out-coupling efficiency becomes larger and smaller (the curved position is raised and then lowered), the slope 20 ° has the reflection out-coupling efficiency relatively highest as a whole, and the slopes 5 °, 10 °, 15 °, 20 °, 30 °, and all have the reflection out-coupling efficiency higher than that without the slope. Accordingly, from the viewpoint of improving the reflection coupling-out efficiency, the pitch angle θ of the end face of the optical unit structure is favorably in the range of 5 ° to 30 °; the pitch angle θ is preferably in the range of 10 ° to 25 °, more preferably in the range of 15 ° to 25 °.

Considering the average coupling-out efficiency before and after splitting on both sides, the tilt pitch angle θ of the optical unit structure is advantageously in the range of 5 ° to 25 °, preferably in the range of 10 ° to 20 °, more preferably in the range of 15 ° to 20 °.

In addition, in combination with the embodiment in which the end face of the optical unit structure shown in fig. 7 includes a combination of a plurality of inclined planes, it is possible to provide more degrees of freedom in optimization for each coupling-out efficiency by adjusting the pitch angle of inclination of the plurality of inclined planes, thereby more optimizing the light utilization efficiency and the uniformity of display of the diffractive optical waveguide device.

Fig. 16 shows an example of a light leakage preventing diffractive optical waveguide device 200 according to the second embodiment of the present invention in a plan view. As shown in fig. 16, the light leakage preventing diffraction optical waveguide device 200 includes a waveguide substrate 200A and an in-grating 210 and an out-grating 220 formed on the waveguide substrate 200A, the out-grating 220 including a two-dimensional grating structure 220A formed on a substrate surface 201 of the waveguide substrate 200A. The light leakage preventing diffractive optical waveguide device 200 may have substantially the same configuration as the light leakage preventing diffractive optical waveguide device 100 according to the first embodiment of the present invention, and the same points are not described herein, but the differences are described in detail below.

According to the second embodiment of the present invention, as shown in fig. 16, the two-dimensional grating structure 220A may include a first region R1 and second regions R21, R22, the end surfaces of the plurality of optical unit structures in the first region R1 include inclined surfaces having the same inclination azimuth angle α1 (corresponding to the "first inclination azimuth"), the end surfaces of the plurality of optical unit structures in the second region R21 include inclined surfaces having the same inclination azimuth angle α21, and the end surfaces of the plurality of optical unit structures in the second region R22 include inclined surfaces having the same inclination azimuth angle α22, and the inclination azimuth angles α21, α22 (corresponding to the "second inclination azimuth") are different from the inclination azimuth angle α1. In other examples, the two-dimensional grating structure 220A may include only one of the second regions R21, R22. Based on the light leakage preventing diffraction optical waveguide device according to the second embodiment, the coupling-out efficiency in the corresponding region can be adjusted by adjusting the inclination azimuth angles of the optical unit structure end surfaces in different regions of the two-dimensional grating structure 220A, so as to meet different performance requirements.

Advantageously, the end faces of the plurality of optical unit structures in the first region R1 comprise a plurality of inclined faces, and the plurality of inclined faces have the same inclination azimuth angle α1; and/or the end surfaces of the plurality of optical unit structures in each second region R21/R22 include a plurality of inclined surfaces, and the plurality of inclined surfaces have the same inclination azimuth angle α21/α22.

Advantageously, the end faces of the plurality of optical unit structures in the first region R1 may be inclined in the same direction with respect to the substrate surface; and/or the end faces of the plurality of optical unit structures in the respective second regions R21, R22 may be inclined in the same direction with respect to the substrate surface.

Advantageously, the out-coupling grating 220 is a reflective out-coupling grating and the tilt azimuth angle α1 is the same as the azimuth angle αin of the IN-coupling direction IN (see fig. 2) along which light propagates from the IN-coupling grating 210 to the out-coupling grating 220 (i.e. the first tilt azimuth is the same as the IN-coupling direction).

Advantageously, the out-coupling grating 220 is a transmissive out-coupling grating and the tilt azimuth angle α1 differs from the azimuth angle αin of the IN-coupling direction IN (see fig. 2) by 180 ° (i.e. the first tilt azimuth is opposite to the IN-coupling direction).

Advantageously, the inclination azimuth angles α21/α22 are each deflected 50 ° -70 °, preferably 60 °, in opposite directions with respect to the inclination azimuth angle α1.

Fig. 17 is a schematic plan view of a light leakage preventing diffractive optical waveguide device 300 according to a third embodiment of the present invention. As shown in fig. 17, the light leakage preventing diffraction optical waveguide device 300 includes a waveguide substrate 300A and an in-grating 310 and an out-grating 320 formed on the waveguide substrate 300A, the out-grating 320 including a two-dimensional grating structure 320A formed on a substrate surface 301 of the waveguide substrate 300A.

The light leakage preventing diffractive optical waveguide device 300 has substantially the same structure as the diffractive optical waveguide device 200 according to the second embodiment, except that: the two-dimensional grating structure 320A further comprises a third region R31, R32 located between the first region R1 and the second region R21, R22.

In the example shown in fig. 17, the end faces of the plurality of optical unit structures in the third region R31 include slopes having the same inclination azimuth angle α31 (corresponding to the "third inclination azimuth"), the end faces of the plurality of optical unit structures in the third region R32 include slopes having the same inclination azimuth angle α32 (corresponding to the "third inclination azimuth"), the inclination azimuth angle α31 is between the inclination azimuth angle α1 and the inclination azimuth angle α21, and the inclination azimuth angle α32 is between the inclination azimuth angle α1 and the inclination azimuth angle α22.

In other examples, the end face of each optical unit structure in the third region R31 includes a slope having a tilt azimuth angle α1 and a slope having a tilt azimuth angle α21, and the end face of each optical unit structure in the third region R32 includes a slope having a tilt azimuth angle α1 and a slope having a tilt azimuth angle α22.

According to the third embodiment of the present invention, by arranging the optical unit structure to have the above-described end face inclination azimuth feature in the third region, more degrees of freedom of the coupling-out efficiency and other optical performance adjustment can be provided.

Fig. 18 is a schematic plan view of a leak-proof diffraction optical waveguide device 300' according to a modification of the third embodiment of the present invention. The diffractive optical waveguide device 300' may have substantially the same structure as the diffractive optical waveguide device 300 shown in fig. 17, except that: the in-coupling grating 310 'in the diffractive optical waveguide device 300 is arranged offset to the left with respect to the out-coupling grating 320'; accordingly, the two-dimensional grating structure 320'a of the outcoupling grating 320' is configured to include a first region R1, a second region R2 located at one side of the first region R1, and a third region R3 located between the first region R1 and the second region R2. Here, the optical unit structures in the first, second, and third regions R1, R2, and R3 may have the same or similar inclined end face structures as described above with reference to fig. 2 to 17, and will not be described again here.

Although in the drawings and the above description the coupling-out grating of the light leakage preventing diffractive optical waveguide device according to the embodiment of the present invention is described as comprising a two-dimensional grating structure, it should be understood that the present invention is not limited to the case where the coupling-out grating comprises only a two-dimensional grating structure; in other embodiments or examples, the out-coupling grating may further comprise a one-dimensional grating, for example one-dimensional gratings arranged on both sides of the two-dimensional grating structure in a direction perpendicular to the in-coupling direction.

The optical waveguide device according to the embodiment of the invention can be applied to display equipment. Such a display device is for example a near-eye display device comprising a lens and a frame for holding the lens close to the eye, wherein the lens may comprise an optical waveguide arrangement according to an embodiment of the invention as described above. Preferably, the display device may be an augmented reality display device or a virtual reality display device.

The light leakage preventing diffraction optical waveguide according to the embodiment of the invention can be applied to a display device. Such a display device may be a near-eye display device comprising a lens and a frame for holding the lens close to the eye, wherein the lens may comprise a light-tight diffractive light guide. Preferably, the display device is an augmented reality display device or a virtual reality display device.

The foregoing description is only of the preferred embodiments of the present application and is presented as a description of the principles of the technology being utilized. It will be appreciated by persons skilled in the art that the scope of the invention referred to in this application is not limited to the specific combinations of features described above, but it is intended to cover other embodiments in which any combination of features described above or equivalents thereof is possible without departing from the spirit of the invention. Such as the above-described features and technical features having similar functions (but not limited to) disclosed in the present application are replaced with each other.

Claims (23)

1. A leak-proof diffraction optical waveguide device comprises a waveguide substrate, and a coupling-in grating and a coupling-out grating formed on the waveguide substrate, wherein

The coupling-in grating is configured to couple an input light beam from outside the waveguide substrate into the waveguide substrate by diffraction and to be propagated to the coupling-out grating by total reflection;

the coupling-out grating includes a two-dimensional grating structure formed on a substrate surface of the waveguide substrate, the two-dimensional grating structure including a structure surface extending in a direction parallel to the substrate surface and a plurality of optical unit structures arranged in an array along the structure surface for expanding light propagating therein by diffraction in a plane parallel to the substrate surface while being coupled out from the waveguide substrate, wherein the optical unit structures are columnar structures and are formed with an end face and a side wall connected between the end face and the structure surface, wherein the end face is inclined with respect to the substrate surface.

2. The light leakage preventing diffraction optical waveguide device of claim 1, wherein the tilt pitch angle of the end faces of the plurality of optical unit structures of the two-dimensional grating structure with respect to the substrate surface is in the range of 5 ° to 25 °.

3. The light leakage preventing diffractive optical waveguide device according to claim 1, wherein the tilt pitch angle is in the range of 10 ° to 20 °.

4. The light leakage preventing diffraction optical waveguide device of claim 1, wherein the columnar structure is a columnar convex structure or a columnar concave hole structure, and the end face is a top face of the convex structure or a bottom face of the concave hole structure.

5. The light leakage preventing diffractive optical waveguide device according to claim 1, wherein the sidewall is perpendicular to the substrate surface.

6. The light leakage preventing diffractive optical waveguide device according to claim 1, wherein the end face comprises at least one inclined face inclined with respect to the substrate surface, each of the inclined faces having a respective inclined orientation, the inclined orientation being a direction in which a projection of a ray perpendicular to the inclined face and directed to a side away from the waveguide substrate onto the substrate surface is directed; and is also provided with

The two-dimensional grating structure includes a first region, and end faces of a plurality of the optical unit structures in the first region include inclined faces having the same first inclination orientation.

7. The light leakage preventing diffractive optical waveguide device according to claim 6, wherein the end surfaces of the plurality of optical units in the first region are inclined in the same direction with respect to the substrate surface.

8. The light leakage preventing diffractive optical waveguide device according to claim 6, wherein the end face of at least one of the optical unit structures in the first region includes a plurality of inclined surfaces, and each of the plurality of inclined surfaces has the first inclined orientation.

9. The light leakage preventing diffractive optical waveguide device according to claim 6, wherein the array includes a plurality of rows perpendicular to a first direction formed by the arrangement of the plurality of optical unit structures, the plurality of rows being arranged at predetermined intervals in the first direction, the optical unit structures being arranged at a period P in the rows, and the optical unit structures in two adjacent rows of the plurality of rows having a misalignment s=p/n in a direction perpendicular to the first direction, wherein 1<n +.5; and the first oblique orientation is parallel to the first direction.

10. The light leakage preventing diffractive optical waveguide device according to claim 9, wherein n=2.

11. The light leakage preventing diffractive optical waveguide device according to claim 6, wherein the out-coupling grating is a reflective out-coupling grating for out-coupling at least a part of light propagating therein in the in-coupling direction by total reflection within the waveguide substrate by diffraction from the waveguide substrate toward an opposite side of a side where the out-coupling grating is located, and the first oblique orientation is the same as the in-coupling direction; or alternatively

The out-coupling grating is a transmissive out-coupling grating for out-coupling at least a portion of light propagating therein in the in-coupling direction by total reflection within the waveguide substrate by diffraction from the waveguide substrate towards a side where the out-coupling grating is located, and the first tilted orientation is opposite to the in-coupling direction.

12. The light leakage preventing diffractive optical waveguide device according to claim 6, wherein the two-dimensional grating structure further comprises a second region, the end faces of the plurality of optical unit structures in the second region comprising inclined faces having the same second inclined orientation, the second inclined orientation being different from the first inclined orientation.

13. The light leakage preventing diffractive optical waveguide device according to claim 12, wherein the two-dimensional grating structure further comprises a third region located between the first region and the second region, the end faces of the plurality of optical unit structures in the third region comprising inclined faces having the same third inclined orientation, the third inclined orientation being intermediate the first inclined orientation and the second inclined orientation.

14. The light leakage prevention diffractive optical waveguide device of claim 12, wherein the two-dimensional grating structure further comprises a third region between the first region and the second region, the end face of each of the optical cell structures in the third region comprising both a chamfer having a first oblique orientation and a chamfer having a second oblique orientation.

15. The light leakage preventing diffractive optical waveguide device according to any one of claims 6 to 14, wherein the edge of the end face has a first point furthest from the substrate surface and a second point closest to the substrate surface, a maximum distance H between points on an intersection line of a virtual plane passing through the first point and the second point and perpendicular to the substrate surface and the end face and a connection line of the points in a height direction perpendicular to the substrate surface _i The method meets the following conditions: h _i And H/3 is less than or equal to H, wherein H is the distance between the first point and the second point in the height direction.

16. The light leakage preventing diffractive optical waveguide device according to any one of claims 6 to 14, wherein the edge of the end face has a first point furthest from the substrate surface and a second point closest to the substrate surface, and each point is progressively reduced or leveled from the substrate surface on an intersection line of a virtual plane passing through the first point and the second point and perpendicular to the substrate surface and the end face from the first point to the second point.

17. The light leakage prevention diffractive optical waveguide device according to any one of claims 1-14, wherein each inclined plane of the end faces of the plurality of optical unit structures of the two-dimensional grating structure has an inclined pitch angle in a range of 5 ° to 30 ° with respect to the substrate surface.

18. The light leakage preventing diffractive optical waveguide device according to claim 9, wherein a projected shape of the optical unit structure on the substrate surface is a longitudinal shape elongated in the first direction.

19. The light leakage prevention diffractive optical waveguide device of claim 18, wherein the elongate shape is diamond, curvilinear diamond, double diamond, curvilinear double diamond, or oval.

20. The light leakage preventing diffractive optical waveguide device according to claim 18, wherein a projected shape of the optical unit structure on the substrate surface is symmetrical or asymmetrical with respect to the first direction.

21. A display device comprising the light-leakage-preventing diffractive optical waveguide according to any one of claims 1 to 20.

22. The display device of claim 21, wherein the display device is a near-eye display device and comprises a lens and a frame for holding the lens close to the eye, the lens comprising the light-leak-proof diffractive optical waveguide.

23. The display device of claim 21 or 22, wherein the display device is an augmented reality display device or a virtual reality display device.