Augmented Reality Waveguide Structure

Abstract

This invention provides an augmented reality waveguide structure. The augmented reality waveguide structure includes a waveguide sheet and coupling gratings and coupling gratings disposed on the waveguide sheet. The coupling grating is a two-dimensional grating, comprising multiple sub-gratings. The coupling grating is divided into a first coupling region and a second coupling region, each containing multiple sub-gratings. The sub-gratings in the first and second coupling regions are identical, but the sub-gratings in the first and second coupling regions are different from each other. This invention solves the problem in existing augmented reality waveguide structures where high efficiency and uniformity are difficult to achieve simultaneously across the entire field of view.

Description

Technical Field

[0001] This invention relates to the field of diffractive optical imaging equipment technology, and more specifically, to an augmented reality waveguide structure. Background Technology

[0002] With the development of diffractive optics and the increasing demand for diffractive optical equipment, various types of diffractive optical devices have emerged. Among them, augmented reality waveguide structures are an important component and currently the mainstream display solution. However, augmented reality waveguide structures suffer from significant differences in transmission efficiency. That is, during the transmission of light in the waveguide sheet, different diffraction regions actually require different diffraction characteristics, but the single grating structure in existing technology is insufficient to meet the diffraction requirements of all viewing angles. Therefore, when designing for the entire field of view, it is often necessary to sacrifice a significant amount of efficiency or uniformity, thereby reducing overall performance.

[0003] Existing technologies typically overcome these shortcomings by altering grating parameters. While changing grating parameters can alter the diffraction distribution of the grating, changes in the grating's morphology are often more effective than altering its depth or duty cycle. Existing gratings are usually symmetrical structures. Although proper grating design can concentrate light efficiency at certain orders, the overall distribution exhibits a symmetrical tendency. This means that the efficiency distribution at symmetrical orders (e.g., the (1,1) and (-1,1) orders of a two-dimensional grating) has the same center angle, while the order trend remains roughly the same at other angles. However, two-dimensional pupil expansion schemes utilize precisely the symmetrical orders of the grating in different regions of the waveguide, thus failing to simultaneously satisfy high efficiency characteristics both above and below the axis.

[0004] In other words, existing augmented reality waveguide structures face the challenge of simultaneously achieving high efficiency and uniformity across the entire field of view. Summary of the Invention

[0005] The main objective of this invention is to provide an augmented reality waveguide structure to solve the problem that existing augmented reality waveguide structures cannot simultaneously achieve high efficiency and uniformity across the entire field of view.

[0006] To achieve the above objectives, the present invention provides an augmented reality waveguide structure, including a waveguide sheet and a coupling grating and a coupling grating disposed on the waveguide sheet. The coupling grating is a two-dimensional grating, which includes multiple sub-gratings. The coupling grating is divided into a first coupling region and a second coupling region. Both the first and second coupling regions have multiple sub-gratings. The multiple sub-gratings in the first coupling region are the same, and the multiple sub-gratings in the second coupling region are the same. The multiple sub-gratings in the first coupling region are different from the multiple sub-gratings in the second coupling region.

[0007] Furthermore, the coupling grating is divided into a first coupling region and a second coupling region along its central axis in the Y-axis direction. The areas of the first coupling region and the second coupling region are equal, and the central axis of the coupling grating in the Y-axis direction coincides with the central axis of the coupling grating in the Y-axis direction.

[0008] Furthermore, the coupling grating is divided into a first coupling region and a second coupling region along its central axis in the Y-axis direction, and the first coupling region and the second coupling region are arranged in a mirror symmetrical manner along the central axis; or the first coupling region is rotated 180° clockwise and has the same structure as the second coupling region.

[0009] Furthermore, the two-dimensional grating has a first grating vector direction and a second grating vector direction, which are set at an acute or obtuse angle, and multiple sub-gratings are arranged at intervals along the first grating vector direction and the second grating vector direction.

[0010] Furthermore, the angle b between the first grating vector direction and the second grating vector direction is 60°.

[0011] Furthermore, the sub-grating includes a first structure and a second structure, the first structure and the second structure being at least partially overlapped, the first structure and the second structure being different in size, and the first structure and the second structure having the same or different heights.

[0012] Furthermore, the overlapping area of ​​the first structure and the second structure projected onto the waveguide sheet is less than half the projected area of ​​the smaller structure in the first structure and the second structure on the waveguide sheet.

[0013] Furthermore, both the first structure and the second structure are cylinders, and the radius of the first structure is smaller than the radius of the second structure; or both the first structure and the second structure are elliptical cylinders, the major axis of the first structure coincides with the major axis of the second structure and the major axis of the first structure is smaller than the major axis of the second structure, and the first structure and the second structure at least partially coincide in the direction of their major axes.

[0014] Furthermore, the projection of the sub-grating onto the waveguide sheet is decagonal, and the projections of the first and second structures of the sub-grating onto the waveguide sheet are arrow-shaped, with each of the three angles of the arrow shape being 60°. The direction of the arrow shape of the first structure is opposite to the direction of the arrow shape of the second structure.

[0015] Furthermore, the sub-gratings are arranged axially symmetrically along the line connecting the vertices of the arrow-shaped structures of the first and second structures, and the line connecting the vertices of the arrow-shaped structures of the first and second structures of all sub-gratings in the two-dimensional grating is parallel to the X-axis or the Y-axis.

[0016] According to the technical solution of the present invention, the augmented reality waveguide structure includes a waveguide sheet and a coupling grating and a coupling grating disposed on the waveguide sheet. The coupling grating is a two-dimensional grating, which includes multiple sub-gratings. The coupling grating is divided into a first coupling region and a second coupling region. Both the first coupling region and the second coupling region have multiple sub-gratings. The multiple sub-gratings in the first coupling region are the same, and the multiple sub-gratings in the second coupling region are the same. The multiple sub-gratings in the first coupling region are different from the multiple sub-gratings in the second coupling region.

[0017] The coupling grating is used to couple light emitted from an external optomechanism into the waveguide sheet and diffract it towards the output grating. The output grating receives the light transmitted from the coupling grating and performs pupil-expanding transmission, ultimately coupling the light out of the waveguide sheet for display in the human eye. By dividing the output grating into a first output region and a second output region, and making multiple sub-gratings in the first output region identical, and multiple sub-gratings in the second output region identical, while the multiple sub-gratings in the first output region and the multiple sub-gratings in the second output region are different, the energy in the first and second output regions can be concentrated into grating orders that expand in different directions. This allows more light from the waveguide sheet to be utilized for display in the human eye, improving the diffraction efficiency of light in the waveguide sheet and enhancing the display efficiency and diffraction uniformity of the augmented reality waveguide structure across the entire field of view. By rationally planning the structure of different regions of the coupling grating, the augmented reality waveguide structure of this application effectively improves the diffraction efficiency under the entire field of view, while making the spatial uniformity and angular uniformity of light entering the eye box better, which greatly improves the display performance and display effect of the augmented reality waveguide structure. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0019] Figure 1 A schematic diagram of an optional form of the augmented reality waveguide structure according to Embodiment 1 of the present invention is shown;

[0020] Figure 2 A schematic diagram of another alternative form of the augmented reality waveguide structure according to Embodiment 1 of the present invention is shown;

[0021] Figure 3 A top view showing one structural form of multiple sub-gratings according to Embodiment 1 of the present invention is shown;

[0022] Figure 4 A top view showing another structural form of the plurality of sub-gratings according to Embodiment 1 of the present invention is shown;

[0023] Figure 5A side view of a sub-grating according to Embodiment 1 of the present invention is shown;

[0024] Figure 6 A schematic diagram of an optional form of the augmented reality waveguide structure according to Embodiment 2 of the present invention is shown;

[0025] Figure 7 A schematic diagram of another optional form of the augmented reality waveguide structure according to Embodiment 2 of the present invention is shown;

[0026] Figure 8 A top view of the sub-grating of Embodiment 2 of the present invention is shown;

[0027] Figure 9 A top view of a plurality of sub-gratings according to Embodiment 2 of the present invention is shown.

[0028] The above figures include the following reference numerals:

[0029] 10. Coupled-in grating; 21. First coupling-out region; 22. Second coupling-out region; 23. Sub-grating; 231. First structure; 232. Second structure; 30. Central axis; K1. First grating vector direction; K2. Second grating vector direction. Detailed Implementation

[0030] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0031] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0032] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0033] To address the problem that existing augmented reality waveguide structures struggle to simultaneously achieve high efficiency and uniformity across the entire field of view, this invention provides an augmented reality waveguide structure.

[0034] like Figures 1 to 9As shown, the augmented reality waveguide structure includes a waveguide sheet and a coupling grating 10 and a coupling grating disposed on the waveguide sheet. The coupling grating is a two-dimensional grating, which includes multiple sub-gratings 23. The coupling grating is divided into a first coupling region 21 and a second coupling region 22. Both the first coupling region 21 and the second coupling region 22 have multiple sub-gratings 23. The multiple sub-gratings 23 in the first coupling region 21 are the same, and the multiple sub-gratings 23 in the second coupling region 22 are the same. The multiple sub-gratings 23 in the first coupling region 21 are different from the multiple sub-gratings 23 in the second coupling region 22.

[0035] The coupling grating 10 is used to couple the light emitted by the external optomechanism into the waveguide sheet and diffract it in the direction of the coupling grating. The coupling grating is used to receive the light transmitted from the coupling grating 10 and perform pupil expansion transmission, and then couple the light out of the waveguide sheet to the human eye for display. By dividing the coupling grating into a first coupling region 21 and a second coupling region 22, and making the multiple sub-gratings 23 in the first coupling region 21 the same, the multiple sub-gratings 23 in the second coupling region 22 the same, and the multiple sub-gratings 23 in the first coupling region 21 different from the multiple sub-gratings 23 in the second coupling region 22, the energy in the first coupling region 21 and the second coupling region 22 can be concentrated to the grating order that expands in different directions. This allows more light efficiency in the waveguide sheet to be utilized for display in the human eye, which is beneficial to improving the diffraction efficiency of light in the waveguide sheet, and at the same time improving the display efficiency and diffraction uniformity of the augmented reality waveguide structure in the full field of view. By rationally planning the structure of different regions of the coupling grating, the augmented reality waveguide structure of this application effectively improves the diffraction efficiency under the entire field of view, while making the spatial uniformity and angular uniformity of light entering the eye box better, which greatly improves the display performance and display effect of the augmented reality waveguide structure.

[0036] like Figure 1 , Figure 2 , Figure 6 and Figure 7As shown, the coupling grating is divided into a first coupling region 21 and a second coupling region 22 along its central axis 30 in the Y-axis direction. The central axis 30 is equivalent to the axis of symmetry of the coupling grating in the Y-axis direction. The areas of the first coupling region 21 and the second coupling region 22 are equal, and the central axis 30 of the coupling grating in the Y-axis direction coincides with the central axis of the coupling grating 10 in the Y-axis direction. The central axis of the coupling grating 10 in the Y-axis direction is also the axis of symmetry of the coupling grating 10 in the Y-axis direction. This arrangement makes the coupling grating evenly divided into the first coupling region 21 and the second coupling region 22, which are set on the left and right respectively. By setting different gratings on the left and right, the energy in the upper half of the waveguide plate is mainly concentrated on the grating order that extends downward, while the energy in the lower half of the plate is mainly concentrated on the grating order that extends upward. This allows more efficiency to be coupled out and received by the human eye. At the same time, the asymmetrical design of the coupling grating can compensate for the asymmetry of efficiency between the upper and lower parts caused by the symmetrical structure itself, and improve uniformity.

[0037] like Figure 1 and Figure 6 In the specific embodiment shown, the first coupling region 21 and the second coupling region 22 are arranged in a mirror-symmetrical manner along the central axis 30. For example... Figure 2 and Figure 7 In the specific embodiment shown, the first coupling region 21, after being rotated 180° clockwise, has the same structure as the second coupling region 22. By different structural arrangements of the left and right first coupling regions 21 and second coupling regions 22, the efficiency direction of the waveguide sheet is effectively planned, increasing diffraction transmission efficiency. This allows the main energy in the upper region to concentrate on the downward-extending grating order, while the efficiency in the lower region is mainly concentrated on the upward-extending grating order. This ensures that most of the light efficiency in the waveguide sheet is coupled out to the human eye for imaging, avoiding waste of light efficiency and guaranteeing that the augmented reality waveguide structure of this application can achieve high-efficiency transmission across the entire field of view. Simultaneously, the asymmetrical design of the coupling gratings compensates for the asymmetry in efficiency caused by traditional symmetrical structures, improving display uniformity. Furthermore, this partitioning of the coupling gratings is not complex in terms of processing and is easy to implement.

[0038] like Figure 3 , Figure 4 and Figure 9The diagram shows a schematic of a two-dimensional grating. The two-dimensional grating has a first grating vector direction K1 and a second grating vector direction K2. The first grating vector direction K1 and the second grating vector direction K2 are set at an acute angle or an obtuse angle. Multiple sub-gratings 23 are arranged at intervals along the two directions of the first grating vector direction K1 and the second grating vector direction K2. That is, multiple sub-gratings 23 are set on both directions. Adjacent sub-gratings 23 on the first grating vector direction K1 are arranged at intervals, and adjacent sub-gratings 23 on the second grating vector direction K2 are arranged at intervals.

[0039] like Figure 3 As shown, the angle b between the first grating vector direction K1 and the second grating vector direction K2 is 60°. By limiting the angle b between the first grating vector direction K1 and the second grating vector direction K2 to 60°, the arrangement of multiple sub-gratings 23 is planned, which is beneficial to increase the diffraction transmission efficiency of the two-dimensional grating, so that more light rays in the waveguide sheet are coupled out by the two-dimensional grating for imaging display.

[0040] Specifically, the sub-grating 23 includes a first structure 231 and a second structure 232. The first structure 231 and the second structure 232 are at least partially overlapped, and their projections on the waveguide sheet are also at least partially overlapping. The first structure 231 and the second structure 232 are different in size; that is, their projections on the waveguide sheet are of different sizes. They can have the same shape but different sizes. In one optional embodiment, the heights of the first structure 231 and the second structure 232 can be the same; in another optional embodiment, the heights of the first structure 231 and the second structure 232 can be different, depending on actual needs. The sub-grating 23 is composed of the first structure 231 and the second structure 232. By rationally planning the shape, size, and height of the first structure 231 and the second structure 232, it is beneficial to modulate the diffraction efficiency of the two-dimensional grating, thereby increasing the overall diffraction uniformity and improving the display effect.

[0041] Specifically, the overlapping area of ​​the projections of the first structure 231 and the second structure 232 on the waveguide sheet is less than half the projected area of ​​the smaller structure of the first structure 231 and the second structure 232 on the waveguide sheet. This helps to constrain the size of the overlapping portion of the first structure 231 and the second structure 232, and avoids the overlapping volume being too large, which would affect the diffraction performance of the sub-grating 23.

[0042] The different forms of the sub-grating 23 of the augmented reality waveguide structure of this application will be described below with reference to specific embodiments.

[0043] Example 1

[0044] like Figures 1 to 5 As shown, the augmented reality waveguide structure of Embodiment 1 is described.

[0045] like Figure 1 As shown, this is an optional form of the augmented reality waveguide structure in Embodiment 1. The coupling grating is divided into a first coupling region 21 and a second coupling region 22, arranged on the left and right sides along the central axis 30. Multiple sub-gratings 23 in the first coupling region 21 have identical structures, and multiple sub-gratings 23 in the second coupling region 22 have identical structures. The multiple sub-gratings 23 in the first coupling region 21 and the multiple sub-gratings 23 in the second coupling region 22 are arranged in a mirror-symmetrical manner along the central axis 30. Each sub-grating 23 in both coupling regions is composed of a first structure 231 and a second structure 232, and both the first structure 231 and the second structure 232 are cylindrical, with the radius of the first structure 231 being smaller than the radius of the second structure 232. The first structure 231 of the sub-grating 23 in the first coupling region 21 is located on the side of the second structure 232 away from the second coupling region 22, and the first structure 231 of the sub-grating 23 in the second coupling region 22 is located on the side of the second structure 232 away from the first coupling region 21.

[0046] like Figure 2 As shown, this is another optional form of the augmented reality waveguide structure in Embodiment 1. Figure 2 Augmented reality waveguide structure and Figure 1 The difference in the augmented reality waveguide structure is that the first coupling region 21, after being rotated 180° clockwise, has the same structure as the second coupling region 22. The first structure 231 of the sub-grating 23 in the first coupling region 21 is located on the side of the second structure 232 facing the coupling grating 10, while the first structure 231 of the sub-grating 23 in the second coupling region 22 is located on the side of the second structure 232 away from the coupling grating 10.

[0047] like Figure 3 As shown, Figure 1 and Figure 2 The figure shows a top view of multiple sub-gratings 23 of the augmented reality waveguide structure. As can be seen from the figure, both the first structure 231 and the second structure 232 are cylindrical, and the radius of the first structure 231 is smaller than the radius of the second structure 232. The overlapping area of ​​the projections of the first structure 231 and the second structure 232 onto the waveguide sheet is less than half the projected area of ​​the first structure 231 onto the waveguide sheet. The angle b between the vector directions K1 and K2 of the first grating and the second grating is 60°.

[0048] like Figure 4 As shown, this is another structural form of multiple sub-gratings 23. Figure 4 The structure of multiple sub-gratings 23 in the middle and Figure 3 The structures of the multiple sub-gratings 23 are different. Figure 4In the sub-grating 23, both the first structure 231 and the second structure 232 are elliptical cylinders. The major axis of the first structure 231 coincides with the major axis of the second structure 232, and the major axis of the first structure 231 is smaller than the major axis of the second structure 232. The first structure 231 and the second structure 232 at least partially coincide in the direction of the major axis, and the overlapping area of ​​the projection of the first structure 231 and the second structure 232 on the waveguide sheet is less than half of the projection area of ​​the first structure 231 on the waveguide sheet.

[0049] The angle b between the first grating vector direction K1 and the second grating vector direction K2 is 60°.

[0050] like Figure 5 As shown, the heights of the first structure 231 and the second structure 232 of the sub-grating 23 in this embodiment can be the same or different. When the heights of the first structure 231 and the second structure 232 are different, the height of the first structure 231 can be less than the height of the second structure 232.

[0051] Example 2

[0052] like Figures 6 to 9 As shown, the augmented reality waveguide structure of Embodiment 2 is described.

[0053] like Figure 6 As shown, this is an optional form of the augmented reality waveguide structure in Embodiment 2. The coupling grating is divided into a first coupling region 21 and a second coupling region 22, arranged on the left and right sides along the central axis 30. Multiple sub-gratings 23 in the first coupling region 21 have identical structures, and multiple sub-gratings 23 in the second coupling region 22 have identical structures. The multiple sub-gratings 23 in the first coupling region 21 and the multiple sub-gratings 23 in the second coupling region 22 are arranged in a mirror-symmetrical manner along the central axis 30. The projections of the sub-gratings 23 in both coupling regions onto the waveguide sheet are decagonal, and each sub-grating 23 is composed of a first structure 231 and a second structure 232. The projections of the first structure 231 and the second structure 232 onto the waveguide sheet are both arrow-shaped, and the size of the first structure 231 is smaller than the size of the second structure 232. The first structure 231 of the sub-grating 23 in the first coupling region 21 is located on the side of the second structure 232 facing the second coupling region 22, and the first structure 231 of the sub-grating 23 in the second coupling region 22 is located on the side of the second structure 232 facing the first coupling region 21.

[0054] like Figure 7 As shown, this is another optional form of the augmented reality waveguide structure in Embodiment 2. Figure 7 Augmented reality waveguide structure and Figure 6The difference in the augmented reality waveguide structure is that the first coupling region 21, after being rotated 180° clockwise, has the same structure as the second coupling region 22. The first structure 231 of the sub-grating 23 in the first coupling region 21 is located on the side of the second structure 232 facing the coupling grating 10, while the first structure 231 of the sub-grating 23 in the second coupling region 22 is located on the side of the second structure 232 away from the coupling grating 10.

[0055] like Figure 8 and Figure 9 As shown, Figure 6 and Figure 7 The image shows a top view of the sub-grating 23. The projection of the sub-grating 23 onto the waveguide sheet is a decagon, and the projections of the first structure 231 and the second structure 232 of the sub-grating 23 onto the waveguide sheet are arrow-shaped. The arrow shape is composed of a triangle and a rectangle, and all three angles of the arrow shape are 60°, that is, all three angles of the triangle that makes up the arrow shape are 60°. The direction of the arrow shape of the first structure 231 is opposite to the direction of the arrow shape of the second structure 232.

[0056] Specifically, the sub-grating 23 is arranged axially symmetrically along the line connecting the vertices of the arrow-shaped structures of the first structure 231 and the second structure 232; for example... Figure 6 As shown, the line connecting the vertices of the arrow-shaped structures of the first structure 231 and the second structure 232 of all sub-gratings 23 in the two-dimensional grating is parallel to the X-axis; as... Figure 7 As shown, the line connecting the arrow-shaped vertices of the first structure 231 and the arrow-shaped vertices of the second structure 232 of all sub-gratings 23 in the two-dimensional grating is parallel to the Y-axis. The arrow-shaped vertex of the first structure 231 is the point farthest from the second structure 232, and the arrow-shaped vertex of the second structure 232 is the point farthest from the first structure 231.

[0057] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0058] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0059] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0060] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An augmented reality waveguide structure, comprising a waveguide sheet and a coupling grating (10) and a coupling grating disposed on the waveguide sheet, wherein the coupling grating is a two-dimensional grating, characterized in that, The two-dimensional grating includes multiple sub-gratings (23). The coupling grating is divided into a first coupling region (21) and a second coupling region (22). Both the first coupling region (21) and the second coupling region (22) have multiple sub-gratings (23). The multiple sub-gratings (23) in the first coupling region (21) are the same, and the multiple sub-gratings (23) in the second coupling region (22) are the same. The multiple sub-gratings (23) in the first coupling region (21) are different from the multiple sub-gratings (23) in the second coupling region (22). It includes a first structure (231) and a second structure (232), the first structure (231) and the second structure (232) are at least partially overlapped, the first structure (231) and the second structure (232) are different in size, and the first structure (231) and the second structure (232) have the same or different heights; the overlapping area of ​​the projection of the first structure (231) and the second structure (232) on the waveguide sheet is less than half of the projection area of ​​the smaller structure of the first structure (231) and the second structure (232) on the waveguide sheet.

2. The augmented reality waveguide structure according to claim 1, characterized in that, The coupling grating is divided into a first coupling region (21) and a second coupling region (22) along its central axis (30) in the Y-axis direction. The areas of the first coupling region (21) and the second coupling region (22) are equal, and the central axis (30) of the coupling grating in the Y-axis direction coincides with the central axis of the coupling grating (10) in the Y-axis direction.

3. The augmented reality waveguide structure according to claim 1, characterized in that, The coupling grating is divided into a first coupling region (21) and a second coupling region (22) along its central axis (30) in the Y-axis direction. The first coupling region (21) and the second coupling region (22) are arranged in a mirror-symmetrical manner along the central axis (30); or The first coupling region (21) has the same structure as the second coupling region (22) after being rotated 180° clockwise.

4. The augmented reality waveguide structure according to claim 1, characterized in that, The two-dimensional grating has a first grating vector direction (K1) and a second grating vector direction (K2), and the first grating vector direction (K1) and the second grating vector direction (K2) are set at an acute angle or an obtuse angle. A plurality of the sub-gratings (23) are arranged at intervals along the first grating vector direction (K1) and the second grating vector direction (K2).

5. The augmented reality waveguide structure according to claim 4, characterized in that, The angle b between the first grating vector direction (K1) and the second grating vector direction (K2) is 60°.

6. The augmented reality waveguide structure according to claim 1, characterized in that, Both the first structure (231) and the second structure (232) are cylinders, and the radius of the first structure (231) is smaller than the radius of the second structure (232); or Both the first structure (231) and the second structure (232) are elliptical cylinders. The major axis of the first structure (231) coincides with the major axis of the second structure (232), and the major axis of the first structure (231) is smaller than the major axis of the second structure (232). The first structure (231) and the second structure (232) at least partially coincide in the direction of the major axis.

7. The augmented reality waveguide structure according to claim 1, characterized in that, The projection of the sub-grating (23) onto the waveguide sheet is decagonal, and the projections of the first structure (231) and the second structure (232) of the sub-grating (23) onto the waveguide sheet are arrow-shaped, with each of the three angles of the arrow shape being 60°. The direction of the arrow shape of the first structure (231) is opposite to the direction of the arrow shape of the second structure (232).

8. The augmented reality waveguide structure according to claim 7, characterized in that, The sub-gratings (23) are arranged axially symmetrically along the line connecting the vertices of the arrow shape of the first structure (231) and the vertices of the arrow shape of the second structure (232) of all the sub-gratings (23) in the two-dimensional grating, and the line connecting the vertices of the arrow shape of the first structure (231) and the vertices of the arrow shape of the second structure (232) of all the sub-gratings (23) is parallel to the X-axis or the Y-axis.

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