Optical waveguide and near-eye display device

Abstract

The utility model provides an optical waveguide and a near-to-eye display device. The optical waveguide comprises a light coupling-out area and a waveguide substrate; the light coupling-out area is arranged on the waveguide substrate; a coupling-out grating is arranged on the light coupling-out area; the coupling-out grating is used for coupling light propagating in the waveguide substrate out of the waveguide substrate and coupling light irradiated to the coupling-out grating from the outside of the waveguide substrate out of the waveguide substrate; the coupling-out grating comprises a plurality of contour edges which are sequentially connected end to end so as to form a preset shape of the coupling-out grating; the coupling-out grating is provided with a minimum circumscribed rectangle, and the minimum circumscribed rectangle is different from the preset shape; the distance between the contour points on any two contour edges of the coupled-out grating in the horizontal direction is smaller than or equal to the maximum horizontal size of the minimum circumscribed rectangle, and the distance between the contour points on any two contour edges of the coupled-out grating in the vertical direction is smaller than or equal to the maximum vertical size of the minimum circumscribed rectangle, so that the light intensity of the rainbow patterns is weakened; and the optical display effect of the optical waveguide is ensured.

Description

Technical Field

[0001] This application relates to the field of optical waveguide technology, and in particular to an optical waveguide and near-eye display device. Background Technology

[0002] Optical waveguides, as key components of near-eye display devices such as augmented reality (AR) devices, possess the function of transmitting optical signals and have good light transmittance, allowing users to view images displayed on the waveguide while simultaneously viewing the real-world environment. Optical waveguides can be designed using diffraction waveguides. For example, an optical waveguide may include a coupling grating. However, coupling gratings exhibit significant dispersion effects. When ambient light from the real environment illuminates the area containing the coupling grating in the optical waveguide, some of the diffracted light is spatially separated according to wavelength and reflected back into the eye, resulting in a colored striped image in the user's field of vision, producing a rainbow effect in the optical waveguide. The presence of this rainbow effect severely interferes with the user's vision, affecting the normal display of the optical waveguide and the user experience of near-eye display devices. Utility Model Content

[0003] This application provides an optical waveguide and a near-eye display device, which aims to reduce the light intensity of rainbow patterns while ensuring the optical display effect of the optical waveguide.

[0004] In a first aspect, this application provides an optical waveguide, the optical waveguide including a light coupling region and a waveguide substrate; the light coupling region is disposed on the waveguide substrate; a coupling grating is disposed on the light coupling region; the coupling grating is used to couple light propagating within the waveguide substrate out of the waveguide substrate, and to couple light irradiated from outside the waveguide substrate to the coupling grating out of the waveguide substrate.

[0005] The coupling grating includes multiple contour edges connected end to end in sequence to form a preset shape of the coupling grating; the coupling grating has a minimum external rectangle, and the minimum external rectangle is different from the preset shape;

[0006] The horizontal distance between contour points on any two contour edges of the coupled grating is less than or equal to the maximum horizontal dimension of the minimum circumscribed rectangle, and the vertical distance between contour points on any two contour edges of the coupled grating is less than or equal to the maximum vertical dimension of the minimum circumscribed rectangle.

[0007] In one embodiment, the contour points of the coupled grating include a first contour point and a second contour point;

[0008] The horizontal distance between a first contour point on any one contour edge of the coupled grating and a second contour point on another contour edge is less than the maximum horizontal dimension of the minimum external rectangle, and the vertical distance between a first contour point on any one contour edge of the coupled grating and a second contour point on another contour edge is less than the maximum vertical dimension of the minimum external rectangle.

[0009] The distance between the second contour points on at least two contour edges of the coupled grating in the horizontal direction is equal to the maximum horizontal dimension of the minimum circumscribed rectangle, and the distance between the second contour points on at least two contour edges of the coupled grating in the vertical direction is equal to the maximum vertical dimension of the minimum circumscribed rectangle.

[0010] In one embodiment, the horizontal projection size of the first contour edge formed by a plurality of sequentially adjacent first contour points in the coupled grating is less than or equal to the maximum horizontal size of the minimum circumscribed rectangle.

[0011] The vertical projection size of the first contour edge formed by a plurality of sequentially adjacent first contour points in the coupled grating is less than or equal to the maximum vertical size of the minimum circumscribed rectangle.

[0012] In one embodiment, when there are at least two first contour edges, and every two adjacent first contour edges intersect at the same second contour point, the horizontal projection size of the at least two first contour edges in the horizontal direction is less than or equal to the maximum horizontal size of the minimum circumscribed rectangle, and the vertical projection size of the at least two first contour edges in the vertical direction is less than or equal to the maximum vertical size of the minimum circumscribed rectangle.

[0013] In one embodiment, the horizontal projection size is greater than or equal to 1 / 7 of the maximum horizontal size of the minimum circumscribed rectangle, and less than or equal to the maximum horizontal size of the minimum circumscribed rectangle;

[0014] The vertical projection size is greater than or equal to 1 / 7 of the maximum vertical size of the minimum circumscribed rectangle, and less than or equal to the maximum horizontal size of the minimum circumscribed rectangle.

[0015] In one embodiment, the first contour edge formed by a plurality of sequentially adjacent first contour points in the coupling grating is recessed toward the center of the coupling grating relative to the second contour edge formed by a plurality of sequentially adjacent second contour points in the coupling grating.

[0016] In one embodiment, the first contour edge formed by a plurality of sequentially adjacent first contour points in the coupled grating includes at least one of the following: a contour edge that is not parallel to the horizontal direction and not parallel to the vertical direction; a contour edge that is partially parallel to the horizontal direction and partially parallel to the vertical direction; a contour edge with a preset angle; and a contour edge with an arc.

[0017] In one embodiment, the preset shape includes one of polygons, circles, ellipses, and irregular shapes.

[0018] In one embodiment, the polygon includes one of a triangle, quadrilateral, pentagon, hexagon, heptagon, octagon, dodecagon, hexagon, and icosagon.

[0019] Secondly, this application also provides a near-eye display device, the near-eye display device including an optomechanism and an optical waveguide as described in any of the embodiments provided in the first aspect; the optomechanism is used to provide light to the optical waveguide; the light coupling region of the optical waveguide couples the light propagating within the waveguide substrate of the optical waveguide to the human eye.

[0020] This application provides an optical waveguide and a near-eye display device. A coupling grating is disposed on the light-exiting region of the optical waveguide. The coupling grating includes multiple sequentially connected contour edges to form a preset shape. The coupling grating has a minimum circumscribed rectangle, which differs from the preset shape. The distance between contour points on any two contour edges of the coupling grating in the horizontal direction is less than or equal to the maximum horizontal dimension of the minimum circumscribed rectangle, and the distance between contour points on any two contour edges of the coupling grating in the vertical direction is less than or equal to the maximum vertical dimension of the minimum circumscribed rectangle. This allows the area of ​​the coupling grating to be smaller than the area of ​​the minimum circumscribed rectangle while simultaneously having a maximum dimension in both the horizontal and vertical directions. When the area of ​​the coupling grating is smaller than the area of ​​the minimum circumscribed rectangle, the amount of light that can reach the coupling grating from outside the waveguide substrate is reduced compared to the minimum circumscribed rectangle, which helps to weaken the intensity of rainbow-like patterns. When the coupling grating has a maximum size in both the horizontal and vertical directions, the optical display effect of the waveguide can be maintained while reducing the light intensity of the rainbow pattern. This achieves a balance between the optical display effect of the waveguide and the light intensity of the rainbow pattern, ensuring a balance between the optical display effect and the visual effect of the waveguide. This reduces the impact of the rainbow pattern on the user, allowing the waveguide to display images normally and improving the user experience of near-eye display devices equipped with the waveguide. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of an optical waveguide provided in an embodiment of this application;

[0023] Figure 2 A schematic diagram of a coupling grating provided in an embodiment of this application;

[0024] Figure 3 This is a schematic diagram of a coupling grating in a related technology;

[0025] Figure 4 This is yet another schematic diagram of a coupling grating provided in an embodiment of this application;

[0026] Figure 5 This is a schematic diagram of the structure of a near-eye display device provided in an embodiment of this application. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] The flowchart shown in the attached diagram is for illustrative purposes only and does not necessarily include all content and operations / steps, nor does it necessarily have to be performed in the order described. For example, some operations / steps can be broken down, combined, or partially merged, so the actual execution order may change depending on the actual situation.

[0029] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0030] In the design of optical waveguides, such as diffractive waveguides, the diffraction effect of the coupling grating is the root cause of rainbow patterns. Understandably, for a given optical waveguide design, the shape and distribution of the rainbow pattern are deterministic. For example, the rainbow pattern may appear in different locations within a person's field of vision, either at the edge or in the center. The presence of rainbow patterns can severely interfere with the user's vision, affecting the normal display of the optical waveguide and the user's experience with near-eye display devices.

[0031] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of an optical waveguide provided in an embodiment of this application.

[0032] like Figure 1 As shown, the optical waveguide includes a light coupling region, a light coupling region, and a waveguide substrate; the light coupling region and the light coupling region are disposed on the waveguide substrate; a coupling grating is disposed on the light coupling region; the light coupling region is used to couple light into the waveguide substrate, and the coupling grating is used to couple light propagating inside the waveguide substrate out of the waveguide substrate, and to couple light irradiated from outside the waveguide substrate to the coupling grating out of the waveguide substrate.

[0033] The coupling grating includes multiple contour edges connected end to end to form a preset shape of the coupling grating; the coupling grating has a minimum circumscribed rectangle, and the minimum circumscribed rectangle is different from the preset shape.

[0034] The horizontal distance between contour points on any two contour edges of the decoupled grating is less than or equal to the maximum horizontal dimension of the minimum circumscribed rectangle, and the vertical distance between contour points on any two contour edges of the decoupled grating is less than or equal to the maximum vertical dimension of the minimum circumscribed rectangle.

[0035] In cases where light propagating within a waveguide substrate is coupled out of the substrate, the coupling grating can be used to effectively couple the light propagating within the waveguide substrate to the outside, such as to the eye box region corresponding to the optical waveguide. Based on this, the optical waveguide can possess optical display functionality.

[0036] The light that shines from outside the waveguide substrate onto the coupling grating can be understood as the ambient light of the environment in which the optical waveguide is located. When the coupling grating couples the light that shines from outside the waveguide substrate onto the coupling grating out of the waveguide substrate, it will produce a rainbow pattern.

[0037] For example, the horizontal and vertical directions can be determined based on the minimum circumscribed rectangle of the coupling grating. The minimum circumscribed rectangle is a hypothetical concept. The fact that the coupling grating has a minimum circumscribed rectangle does not imply that a corresponding minimum circumscribed rectangle is actually placed on the optical waveguide. For instance, the fact that the coupling grating has a minimum circumscribed rectangle does not mean that a corresponding minimum circumscribed rectangle is placed on the waveguide substrate of the optical waveguide. The minimum circumscribed rectangle of the coupling grating can include two long sides and two short sides, which are connected end-to-end and perpendicular to each other. When determining the minimum circumscribed rectangle of the coupling grating, for example, the horizontal direction can be determined based on the long side of the minimum circumscribed rectangle, and the vertical direction can be determined based on the short side. In this case, the maximum horizontal dimension of the minimum circumscribed rectangle is equal to the length of its long side, and the maximum vertical dimension is equal to the length of its short side. Of course, it is not limited to this. In the case of determining the minimum external rectangle of the coupling grating, for example, the horizontal direction can be determined based on the short side of the minimum external rectangle, and the vertical direction can be determined based on the long side of the minimum external rectangle. Then the maximum horizontal dimension of the minimum external rectangle is equal to the length of the short side of the minimum external rectangle, and the maximum vertical dimension of the minimum external rectangle is equal to the length of the long side of the minimum external rectangle.

[0038] Since the preset shape of the coupling grating differs from its minimum circumscribed rectangle, and the minimum circumscribed rectangle can cover the preset shape of the coupling grating, the area of ​​the coupling grating is smaller than the area of ​​the minimum circumscribed rectangle. It can be understood that the preset shape of the coupling grating is essentially obtained by adjusting the shape of the minimum circumscribed rectangle. The preset shape of the coupling grating can include a non-hollow shape or a hollow shape. In an exemplary embodiment, the preset shape of the coupling grating is a non-hollow shape. When the preset shape of the coupling grating is a non-hollow shape, it is equivalent to retaining the central region of the coupling grating. Since the central region of the coupling grating can fit within the main viewing area of ​​the human eye, i.e., the middle area within the user's visual field, and users tend to view content through their main viewing area, retaining the central region of the coupling grating improves the user's visual experience when viewing content displayed on the waveguide. Of course, this is not limited to this; the preset shape of the coupling grating can also be directly designed, in which case the preset shape of the coupling grating can still have a corresponding minimum circumscribed rectangle. Rainbow patterns can only be produced when light from outside the waveguide substrate illuminates the coupling grating. If the area of ​​the coupling grating is smaller than the area of ​​the minimum circumscribed rectangle, light that theoretically could reach the minimum circumscribed rectangle from outside the waveguide substrate may actually be unable to reach the coupling grating. Therefore, by using a preset shape for the coupling grating that differs from the minimum circumscribed rectangle, the amount of light illuminating the coupling grating from outside the waveguide substrate can be reduced, thereby weakening the intensity of the rainbow patterns.

[0039] For example, the coupling grating may include multiple periodically arranged unit structures. The preset shape of the coupling grating may be a shape formed by the multiple periodically arranged unit structures, such as a shape determined by multiple unit structures located in the edge region of the coupling grating, rather than the shape of individual unit structures.

[0040] like Figure 2 (a) to Figure 2 As shown in (c), taking a coupling grating including coupling grating a, coupling grating b, and coupling grating c as an example. Coupling gratings a, b, and c all have the same minimum bounding rectangle. The same minimum bounding rectangle means that the minimum bounding rectangles of coupling gratings a, b, and c completely overlap. The area of ​​coupling grating a is larger than the area of ​​coupling grating b, the area of ​​coupling grating b is larger than the area of ​​coupling grating c, and the maximum horizontal dimension of each of coupling gratings a to c is equal to the maximum horizontal dimension of the minimum bounding rectangle, and the maximum vertical dimension of each of coupling gratings a to c is equal to the maximum vertical dimension of the minimum bounding rectangle.

[0041] like Figure 3 As shown, the shape of the coupling grating in the related art can completely coincide with the shape of the minimum external rectangle of the coupling grating in this application, such as coupling gratings a to c. For example, in coupling grating a, the side length of the contour edge parallel to the horizontal direction is half the maximum horizontal dimension of the minimum external rectangle, and the side length of the contour edge parallel to the vertical direction is half the maximum vertical dimension of the minimum external rectangle; in coupling grating b, the side length of the contour edge parallel to the horizontal direction is one-third the maximum horizontal dimension of the minimum external rectangle, and the side length of the contour edge parallel to the vertical direction is one-third the maximum vertical dimension of the minimum external rectangle; and in coupling grating c, the horizontal projection dimension of each contour edge in the horizontal direction is half the maximum horizontal dimension of the minimum external rectangle, and the vertical projection dimension of each contour edge in the vertical direction is half the maximum vertical dimension of the minimum external rectangle. The area of ​​coupling grating a is larger than that of coupling grating b, the area of ​​coupling grating b is larger than that of coupling grating c, and the areas of each of coupling gratings a to c are smaller than the area of ​​the smallest circumscribed rectangle corresponding to all of them, which is equivalent to being smaller than the area of ​​the coupling gratings in the related technology. By comparing the light intensity of the rainbow fringes produced by the coupling gratings a, b, and c in the related technology under the same illumination conditions, the relative intensity of the rainbow fringes of each coupling grating a, b, and c relative to the coupling gratings in the related technology can be obtained, as shown in the table below:

[0042]

[0043] Based on this, it can be determined that when the area of ​​the coupling grating is smaller than the area of ​​the minimum circumscribed rectangle, that is, when the areas of each of the coupling gratings a to c are smaller than the area of ​​the coupling grating in the related technology, as the area difference between the area of ​​the coupling grating and the area of ​​the minimum circumscribed rectangle increases, the reduction in the light intensity of the rainbow pattern increases.

[0044] When the preset shape of the coupling grating differs from that of the minimum circumscribed rectangle (i.e., the area of ​​the coupling grating is smaller than that of the minimum circumscribed rectangle), the light intensity that the coupling grating can effectively couple to the corresponding eye box region of the optical waveguide will decrease accordingly, resulting in light loss. This may affect the display effect of the optical waveguide. For example, when near-eye display devices utilize optical waveguides to achieve near-eye display functions, problems such as reduced display brightness or uneven brightness distribution may occur. The larger the area difference between the coupling grating and the minimum circumscribed rectangle, the greater the reduction in the light intensity of the rainbow pattern, and the greater the reduction in the optical display performance of the optical waveguide. Therefore, in order to reduce the light intensity of the rainbow pattern while maintaining the optical display effect of the optical waveguide, and thus achieve a balance between the optical display effect of the optical waveguide and the light intensity of the rainbow pattern—that is, to ensure a balance between the optical display effect and the visual effect of the optical waveguide—the area difference between the coupling grating and the minimum circumscribed rectangle is limited by the maximum horizontal and vertical dimensions of the minimum circumscribed rectangle.

[0045] Since the horizontal distance between the contour points on any two contour edges of the coupling grating is less than or equal to the maximum horizontal dimension of the minimum circumscribed rectangle, and the vertical distance between the contour points on any two contour edges of the coupling grating is less than or equal to the maximum vertical dimension of the minimum circumscribed rectangle, it can be determined that the coupling grating has a maximum dimension in both the horizontal and vertical directions. The maximum horizontal dimension of the coupling grating is equal to the maximum horizontal dimension of the minimum circumscribed rectangle, and the maximum vertical dimension of the coupling grating is equal to the maximum vertical dimension of the minimum circumscribed rectangle. Based on this, a certain range of area difference can be maintained between the area of ​​the coupling grating and the area of ​​the minimum circumscribed rectangle to ensure that the optical waveguide maintains its optical display effect while reducing the intensity of the rainbow effect.

[0046] In one embodiment, the contour points of the coupling grating include a first contour point and a second contour point; the horizontal distance between the first contour point on any contour edge of the coupling grating and the second contour point on another contour edge is less than the maximum horizontal dimension of the minimum circumscribed rectangle, and the vertical distance between the first contour point on any contour edge of the coupling grating and the second contour point on another contour edge is less than the maximum vertical dimension of the minimum circumscribed rectangle; the horizontal distance between the first contour points on at least two contour edges of the coupling grating is equal to the maximum horizontal dimension of the minimum circumscribed rectangle, and the vertical distance between the second contour points on at least two contour edges of the coupling grating is equal to the maximum vertical dimension of the minimum circumscribed rectangle.

[0047] like Figure 2As shown in (a), for the contour points included in the coupling grating a, contour points that do not coincide with the contour points of the minimum circumscribed rectangle of the coupling grating a can be defined as first contour points, and contour points that coincide with the contour points of the minimum circumscribed rectangle of the coupling grating a can be defined as second contour points. Since the horizontal distance between contour points on any two contour edges of the coupling grating a is limited by the maximum horizontal dimension of the minimum circumscribed rectangle of the coupling grating a, and the vertical distance between contour points on any two contour edges of the coupling grating a is limited by the maximum vertical dimension of the minimum circumscribed rectangle of the coupling grating a, the horizontal distance between the first contour point on one contour edge of the coupling grating a and the second contour point on another contour edge is less than the maximum horizontal dimension of the minimum circumscribed rectangle of the coupling grating a, and the vertical distance between the first contour point on one contour edge of the coupling grating a and the second contour point on another contour edge is less than the maximum vertical dimension of the minimum circumscribed rectangle of the coupling grating a. Accordingly, the coupling grating a has at least two contour points on its contour edges such that the horizontal distance between the second contour points is equal to the maximum horizontal dimension of the smallest circumscribed rectangle of the coupling grating a, and the vertical distance between the second contour points on at least two contour edges of the coupling grating a is equal to the maximum vertical dimension of the smallest circumscribed rectangle of the coupling grating a. For example, for two contour edges parallel to the vertical direction in the coupling grating a, the horizontal distance between the second contour points on one contour edge and the second contour points on the other contour edge is equal to the maximum horizontal dimension of the smallest circumscribed rectangle of the coupling grating a. As another example, for two contour edges parallel to the horizontal direction in the coupling grating a, the vertical distance between the second contour points on one contour edge and the second contour points on the other contour edge is equal to the maximum vertical dimension of the smallest circumscribed rectangle of the coupling grating a. When the preset shape of the coupling grating is the same as or similar to the preset shape of the coupling grating a, the central region of the coupling grating can be preserved while increasing the area difference between the coupling grating and the smallest circumscribed rectangle of the coupling grating. Since the central region of the coupling grating can be adapted to the main area of ​​human eye focus, that is, the middle area within the user's visual field, and users tend to view the corresponding content through the main area of ​​human eye focus, retaining the central region of the coupling grating is beneficial to improving the user's visual experience when viewing the content displayed on the optical waveguide.

[0048] like Figure 2As shown in (c), for the contour points included in the coupling grating c, contour points that do not coincide with the contour points of the smallest circumscribed rectangle of the coupling grating c can be defined as first contour points, and contour points that coincide with the contour points of the smallest circumscribed rectangle of the coupling grating c can be defined as second contour points. For example, the preset shape of the coupling grating c can also be called a rhombus. The vertices of the rhombus can be used as the second contour points of the coupling grating c. Contour points in the rhombus other than the vertices can be used as the first contour points of the coupling grating c. For example, the horizontal distance between a first contour point on any contour edge and a second contour point on another contour edge in the coupling grating c is less than the maximum horizontal dimension of the smallest circumscribed rectangle of the coupling grating c, and the vertical distance between a first contour point on any contour edge and a second contour point on another contour edge in the coupling grating c is less than the maximum vertical dimension of the smallest circumscribed rectangle of the coupling grating c. For example, for two sets of opposite vertices in the coupling grating c, the horizontal distance between one set of opposite vertices is equal to the maximum horizontal distance of the minimum external rectangle of the coupling grating c, and the vertical distance between the other set of opposite vertices is equal to the maximum vertical distance of the minimum external rectangle of the coupling grating c.

[0049] Of course, the coupling grating is not limited to this; the preset shape of the coupling grating can be diverse, such as... Figure 4 (a) to Figure 4 As shown in (s) in the figure, there are no restrictions here.

[0050] When the horizontal distance between a first contour point on any contour edge of the coupling grating and a second contour point on another contour edge, and the horizontal distance between second contour points on at least two contour edges, are limited by the maximum horizontal dimension of the minimum circumscribed rectangle of the coupling grating, and the vertical distance between a first contour point on any contour edge of the coupling grating and a second contour point on another contour edge, and the vertical distance between second contour points on at least two contour edges, are limited by the maximum vertical dimension of the minimum circumscribed rectangle of the coupling grating, the coupling grating can reduce the light intensity of the rainbow pattern in the optical waveguide while ensuring the optical display effect of the optical waveguide.

[0051] In one embodiment, the horizontal projection size of the first contour edge formed by a plurality of sequentially adjacent first contour points in the coupling grating is less than or equal to the maximum horizontal size of the minimum circumscribed rectangle in the horizontal direction; the vertical projection size of the first contour edge formed by a plurality of sequentially adjacent first contour points in the coupling grating is less than or equal to the maximum vertical size of the minimum circumscribed rectangle in the vertical direction.

[0052] For example, the horizontal projection dimension of the first contour edge in the horizontal direction can be greater than 0 and less than or equal to the maximum horizontal dimension of the minimum circumscribed rectangle. Correspondingly, the vertical projection dimension of the first contour edge in the vertical direction can be greater than 0 and less than or equal to the maximum vertical dimension of the minimum circumscribed rectangle.

[0053] like Figure 2 As shown in (a), taking the example where the side length of the contour edge parallel to the horizontal direction in the coupling grating a is half of the maximum horizontal dimension of the minimum circumscribed rectangle, and the side length of the contour edge parallel to the vertical direction in the coupling grating a is half of the maximum vertical dimension of the minimum circumscribed rectangle, and the shape of the coupling grating a is symmetrical. Since the first and last first contour points in the first contour edge formed by a plurality of sequentially adjacent first contour points in the coupling grating a are infinitely close to their respective adjacent second contour points, the horizontal projection dimension of the first contour edge formed by a plurality of sequentially adjacent first contour points in the coupling grating a is equal to 1 / 4 of the maximum horizontal dimension of the minimum circumscribed rectangle, and the vertical projection dimension is equal to 1 / 4 of the maximum vertical dimension of the minimum circumscribed rectangle.

[0054] like Figure 2 As shown in (b), taking the example where the side length of the contour edge parallel to the horizontal direction in the coupling grating b is 1 / 3 of the maximum horizontal dimension of the minimum circumscribed rectangle, and the side length of the contour edge parallel to the vertical direction in the coupling grating b is 1 / 3 of the maximum vertical dimension of the minimum circumscribed rectangle, and the shape of the coupling grating b is symmetrical. Since the first and last first contour points in the first contour edge formed by a plurality of sequentially adjacent first contour points in the coupling grating b are infinitely close to their respective adjacent second contour points, the horizontal projection dimension of the first contour edge formed by a plurality of sequentially adjacent first contour points in the coupling grating b in the horizontal direction is equal to 1 / 3 of the maximum horizontal dimension of the minimum circumscribed rectangle, and the vertical projection dimension in the vertical direction is equal to 1 / 3 of the maximum vertical dimension of the minimum circumscribed rectangle.

[0055] like Figure 2As shown in (c), since the shape of the coupling grating c is rhomboid and the rhombus has symmetry, the first contour edge formed by multiple consecutively adjacent first contour points in the coupling grating c can be the hypotenuse of the rhombus. The horizontal projection dimension of the hypotenuse of the rhombus in the horizontal direction is equal to half the length of the diagonal of the rhombus in the horizontal direction, which is equal to half the maximum horizontal dimension of the smallest circumscribed rectangle. The vertical projection dimension of the hypotenuse of the rhombus in the vertical direction is equal to half the length of the diagonal of the rhombus in the vertical direction, which is equal to half the maximum vertical dimension of the smallest circumscribed rectangle. If the horizontal projection dimension of the first contour edge of the coupling grating c in the horizontal direction is equal to half of the maximum horizontal dimension of the minimum circumscribed rectangle of the coupling grating c, and the vertical projection dimension of the first contour edge of the coupling grating c in the vertical direction is equal to half of the maximum vertical dimension of the minimum circumscribed rectangle of the coupling grating c, and there exist two adjacent first contour edges in the coupling grating c whose horizontal projection dimensions in the horizontal direction are equal to the maximum horizontal dimension of the minimum circumscribed rectangle of the coupling grating c, and there exist two other adjacent first contour edges in the coupling grating c whose vertical projection dimensions in the vertical direction are equal to the maximum vertical dimension of the minimum circumscribed rectangle of the coupling grating c, then the coupling grating c can, under the constraints of the maximum horizontal and maximum vertical dimensions of the minimum circumscribed rectangle of the coupling grating c, maximize the area difference between the coupling grating c and the minimum circumscribed rectangle of the coupling grating c. This is beneficial to maximize the reduction of the light intensity of the rainbow pattern by the coupling grating c while maintaining the balance between the optical display effect of the optical waveguide and the light intensity of the rainbow pattern.

[0056] For example, the preset shape of the coupling grating may include a triangle, such as a right triangle, an isosceles triangle, etc.

[0057] Taking a right-angled triangle as the preset shape of the coupling grating as an example, the first contour side formed by multiple adjacent first contour points in the coupling grating can be the hypotenuse of the right-angled triangle. The horizontal projection size of the hypotenuse of the right-angled triangle in the horizontal direction is equal to the maximum horizontal size of the smallest circumscribed rectangle of the right-angled triangle, and the vertical projection size of the hypotenuse of the right-angled triangle in the vertical direction is equal to the maximum vertical size of the smallest circumscribed rectangle of the right-angled triangle. When the horizontal projection size of the first contour side of the coupling grating in the horizontal direction is equal to the maximum horizontal size of the smallest circumscribed rectangle of the coupling grating, and the vertical projection size of the first contour side of the coupling grating in the vertical direction is equal to the maximum vertical size of the smallest circumscribed rectangle of the coupling grating, the coupling grating can, under the constraints of the maximum horizontal and maximum vertical sizes of the smallest circumscribed rectangle of the coupling grating, maximize the area difference between the coupling grating and the smallest circumscribed rectangle of the coupling grating. This helps to maximize the reduction of the light intensity of the rainbow pattern by the coupling grating while maintaining a balance between the optical display effect of the waveguide and the light intensity of the rainbow pattern.

[0058] Taking an isosceles triangle as the preset shape of the coupling grating as an example, the first contour edge formed by multiple sequentially adjacent contour points in the coupling grating can be the legs of the isosceles triangle. The two legs of the isosceles triangle can serve as two adjacent first contour edges in the coupling grating. The horizontal projection dimension of the legs of the isosceles triangle in the horizontal direction is equal to half the maximum horizontal dimension of the smallest circumscribed rectangle of the isosceles triangle, and the vertical projection dimension of the legs of the isosceles triangle in the vertical direction is equal to half the maximum vertical dimension of the smallest circumscribed rectangle of the isosceles triangle. The horizontal projection dimension of the two legs of the isosceles triangle in the horizontal direction is equal to the maximum horizontal dimension of the smallest circumscribed rectangle of the isosceles triangle, and the vertical projection dimension of the two legs of the isosceles triangle in the vertical direction is equal to the maximum vertical dimension of the smallest circumscribed rectangle of the isosceles triangle. Therefore, the two legs of the isosceles triangle are equivalent to two adjacent first contour edges in the coupling grating. Correspondingly, for coupling gratings with a preset shape other than right-angled triangles and isosceles triangles, since a triangle has a minimum circumscribed rectangle, the sides of the triangle that are not parallel to the horizontal direction and not parallel to the vertical direction are equivalent to the first contour sides of the coupling grating. For coupling gratings with a preset triangular shape, the horizontal projection size corresponding to the two adjacent first contour sides in the horizontal direction is equal to the maximum horizontal size of the minimum circumscribed rectangle of the coupling grating, and the vertical projection size corresponding to the two adjacent first contour sides in the vertical direction is equal to the maximum vertical size of the minimum circumscribed rectangle of the coupling grating. Therefore, under the constraints of the maximum horizontal and maximum vertical size of the minimum circumscribed rectangle of the coupling grating, the area difference between the coupling grating and the minimum circumscribed rectangle of the coupling grating can be maximized. This helps to maximize the reduction of the light intensity of the rainbow pattern by the coupling grating while maintaining the balance between the optical display effect of the optical waveguide and the light intensity of the rainbow pattern.

[0059] Of course, the preset shape of the coupling grating is not limited to this, and no restrictions are imposed here.

[0060] For example, a plurality of sequentially adjacent first contour points in a coupling grating can form a first contour edge of the coupling grating. The coupling grating may include at least one first contour edge. When multiple first contour edges exist, the horizontal projection size of each first contour edge in the horizontal direction is less than or equal to the maximum horizontal size of the minimum circumscribed rectangle, and the horizontal projection sizes of different first contour edges in the horizontal direction may be the same or different. Correspondingly, the vertical projection size of each first contour edge in the vertical direction is less than or equal to the maximum horizontal size of the minimum circumscribed rectangle, and the vertical projection sizes of different first contour edges in the vertical direction may be the same or different, without limitation.

[0061] When the horizontal projection size of the first contour edge formed by a plurality of adjacent first contour points in the coupled grating is less than or equal to the maximum horizontal size of the minimum circumscribed rectangle, and the vertical projection size of the first contour edge formed by a plurality of adjacent first contour points in the coupled grating is less than or equal to the maximum vertical size of the minimum circumscribed rectangle, it can be ensured that the distance between the contour points on any two contour edges of the coupled grating in the horizontal direction is less than or equal to the maximum horizontal size of the minimum circumscribed rectangle, and the distance between the contour points on any two contour edges of the coupled grating in the vertical direction is less than or equal to the maximum vertical size of the minimum circumscribed rectangle. This allows the coupled grating to reduce the light intensity of the rainbow pattern while ensuring the optical display effect of the optical waveguide.

[0062] In one embodiment, when there are at least two first contour edges, and every two adjacent first contour edges intersect at the same second contour point, the horizontal projection size of the at least two first contour edges in the horizontal direction is less than or equal to the maximum horizontal size of the minimum circumscribed rectangle, and the vertical projection size of the at least two first contour edges in the vertical direction is less than or equal to the maximum vertical size of the minimum circumscribed rectangle.

[0063] like Figure 2 As shown in (c), since the shape of the coupling grating c is rhomboid, the hypotenuse of the rhombus is equivalent to the first contour edge of the coupling grating c. Each pair of adjacent hypotenuses of the rhombus intersects at the same vertex, which is equivalent to the second contour point. The horizontal projection dimension corresponding to at least two first contour edges of the rhombus in the horizontal direction is equal to the maximum horizontal dimension of the minimum circumscribed rectangle, and the vertical projection dimension corresponding to at least two first contour edges of the rhombus in the vertical direction is equal to the maximum vertical dimension of the minimum circumscribed rectangle.

[0064] For example, when the shape of the coupling grating is triangular, the triangle can have two first contour edges that are neither parallel to the horizontal nor parallel to the vertical direction, and the two adjacent first contour edges of the triangle intersect at the same vertex, which is equivalent to the second contour point. The horizontal projection dimension corresponding to the two adjacent first contour edges of the triangle in the horizontal direction is equal to the maximum horizontal dimension of the minimum circumscribed rectangle, and the vertical projection dimension corresponding to the two adjacent first contour edges of the triangle in the vertical direction is equal to the maximum vertical dimension of the minimum circumscribed rectangle.

[0065] Of course, the coupling grating is not limited to this, and no restrictions are imposed here.

[0066] When the horizontal projection size corresponding to at least two first contour edges in the horizontal direction is less than or equal to the maximum horizontal size of the minimum circumscribed rectangle, and the vertical projection size corresponding to at least two first contour edges in the vertical direction is less than or equal to the maximum vertical size of the minimum circumscribed rectangle, it can be ensured that the distance between contour points on any two contour edges of the coupled grating in the horizontal direction is less than or equal to the maximum horizontal size of the minimum circumscribed rectangle, and the distance between contour points on any two contour edges of the coupled grating in the vertical direction is less than or equal to the maximum vertical size of the minimum circumscribed rectangle. This allows the coupled grating to reduce the light intensity of the rainbow pattern while ensuring the optical display effect of the optical waveguide.

[0067] In one embodiment, the horizontal projection size is greater than or equal to 1 / 7 of the maximum horizontal size of the minimum circumscribed rectangle, and less than or equal to the maximum horizontal size of the minimum circumscribed rectangle.

[0068] For example, the horizontal projection size may include one of the following: 1 / 7, 2 / 7, 3 / 7, 4 / 7, 1 / 6, 1 / 5, 1 / 4, 1 / 3, 1 / 2, 2 / 3, etc., which is the maximum horizontal size of the smallest circumscribed rectangle.

[0069] In one embodiment, the vertical projection size is greater than or equal to 1 / 7 of the maximum vertical size of the minimum circumscribed rectangle, and less than or equal to the maximum vertical size of the minimum circumscribed rectangle.

[0070] For example, the vertical projection size may include one of the following: 1 / 7, 2 / 7, 3 / 7, 4 / 7, 1 / 6, 1 / 5, 1 / 4, 1 / 3, 1 / 2, 2 / 3, etc., of the maximum vertical size of the minimum circumscribed rectangle.

[0071] Understandably, a coupling grating may have at least one first contour edge. The horizontal projected dimensions of the different first contour edges included in the coupling grating may be the same or different. For example, the horizontal projected dimensions of all the first contour edges in the coupling grating may include at least one of the following: 1 / 7, 2 / 7, 3 / 7, 4 / 7, 1 / 6, 1 / 5, 1 / 4, 1 / 3, 1 / 2, 2 / 3, etc., of the maximum horizontal dimension of the smallest circumscribed rectangle. Correspondingly, the vertical projected dimensions of the different first contour edges included in the coupling grating may be the same or different. The horizontal and vertical projected dimensions of the same first contour edge included in the coupling grating may be the same or different. For example, the vertical projected dimensions of all the first contour edges in the coupling grating may include at least one of the following: 1 / 7, 2 / 7, 3 / 7, 4 / 7, 1 / 6, 1 / 5, 1 / 4, 1 / 3, 1 / 2, 2 / 3, etc., of the maximum vertical dimension of the smallest circumscribed rectangle. No limitations are imposed here.

[0072] When the horizontal projection size is greater than or equal to 1 / 7 of the maximum horizontal size of the minimum circumscribed rectangle, and less than or equal to the maximum horizontal size of the minimum circumscribed rectangle, it can be ensured that the horizontal distance between contour points on any two contour edges of the coupled grating is less than or equal to the maximum horizontal size of the minimum circumscribed rectangle, while maximizing the area difference between the coupled grating and its minimum circumscribed rectangle. Correspondingly, when the vertical projection size is greater than or equal to 1 / 7 of the maximum vertical size of the minimum circumscribed rectangle, and less than or equal to the maximum vertical size of the minimum circumscribed rectangle, it can be ensured that the vertical distance between contour points on any two contour edges of the coupled grating is less than or equal to the maximum vertical size of the minimum circumscribed rectangle, while maximizing the area difference between the coupled grating and its minimum circumscribed rectangle. As the horizontal projection size increases, the area difference between the coupled grating and its minimum circumscribed rectangle also increases accordingly. As the vertical projection size increases, the area difference between the coupled grating and its minimum circumscribed rectangle also increases accordingly. When the area difference between the minimum circumscribed rectangles of the coupling gratings increases, it is beneficial to improve the reduction of the light intensity of the rainbow pattern. This allows the optical waveguide to maintain its optical display effect while minimizing the light intensity of the rainbow pattern, thus achieving a balance between the optical display effect of the optical waveguide and the light intensity of the rainbow pattern.

[0073] In one embodiment, the first contour edge formed by a plurality of sequentially adjacent first contour points in the coupling grating is recessed toward the center of the coupling grating relative to the second contour line formed by a plurality of sequentially adjacent second contour points in the coupling grating.

[0074] like Figure 2 (a) to Figure 2 (c) and Figure 4 (a) to Figure 4As shown in (s), the second contour edge formed by a plurality of sequentially adjacent second contour points in the coupling grating can coincide with the edge of the smallest circumscribed rectangle of the coupling grating, while the first contour edge formed by a plurality of sequentially adjacent first contour points in the coupling grating deviates from the edge of the smallest circumscribed rectangle of the coupling grating, that is, the first contour edge is concave towards the center of the coupling grating. Accordingly, the smaller the average distance between each of the plurality of first contour points included in the coupling grating and the centerline of the smallest circumscribed rectangle of the coupling grating, the greater the area difference between the smallest circumscribed rectangles of the coupling gratings, which is beneficial to maximize the reduction of the light intensity of the rainbow pattern by the coupling grating while maintaining the balance between the optical display effect of the optical waveguide and the light intensity of the rainbow pattern. Furthermore, when the first contour edge formed by a plurality of sequentially adjacent first contour points in the coupling grating is concave towards the center of the coupling grating, the preset shape of the coupling grating can retain the central region of the coupling grating. Since the central region of the coupling grating can be adapted to the area where the user's eyes mainly focus, such as the central region of the user's visual range, and users usually look at the central region of the waveguide when viewing the content displayed on the waveguide, such as the central region of the coupling grating, retaining the central region of the coupling grating helps to improve the reduction of the light intensity of the rainbow pattern by the coupling grating, while maintaining the balance between the optical display effect of the waveguide and the light intensity of the rainbow pattern, and improving the user's visual experience of the waveguide, such as improving the visual clarity and comfort of the user when viewing the content displayed on the waveguide.

[0075] When the first contour edge formed by a plurality of adjacent first contour points in the coupling grating is recessed toward the center of the coupling grating, it can be ensured that the distance between the contour points on any two contour edges of the coupling grating in the horizontal direction is less than or equal to the maximum horizontal dimension of the minimum circumscribed rectangle, and the distance between the contour points on any two contour edges of the coupling grating in the vertical direction is less than or equal to the maximum vertical dimension of the minimum circumscribed rectangle. This allows the coupling grating to reduce the light intensity of the rainbow pattern in the optical waveguide while ensuring the optical display effect of the optical waveguide.

[0076] In one embodiment, the first contour edge formed by a plurality of sequentially adjacent first contour points in the coupling grating includes at least one of the following: a contour edge that is not parallel to the horizontal direction and not parallel to the vertical direction; a contour edge that is partially parallel to the horizontal direction and partially parallel to the vertical direction; a contour edge with a preset angle; and a contour edge with an arc.

[0077] For example, the first contour edge formed by a plurality of sequentially adjacent first contour points in the coupling grating does not coincide with the edge of the smallest external rectangle of the coupling grating. The second contour edge formed by a plurality of sequentially adjacent second contour points in the coupling grating partially coincides with the edge of the smallest external rectangle of the coupling grating.

[0078] like Figure 2 (a) to Figure 2 (c) Figure 4 (a) to Figure 4 (in) l )as well as Figure 4 As shown in (s), the first contour edge formed by a plurality of sequentially adjacent first contour points in the coupling grating may include a contour edge that is neither parallel to the horizontal direction nor parallel to the vertical direction.

[0079] like Figure 4 (m) in Figure 4 (p) and Figure 4 As shown in (s), the first contour edge formed by a plurality of sequentially adjacent first contour points in the coupling grating may include a contour edge that is partially parallel to the horizontal direction and partially parallel to the vertical direction.

[0080] like Figure 4 (q) and Figure 4 As shown in (s), the first contour edge formed by a plurality of sequentially adjacent first contour points in the coupled grating may include a contour edge with an included angle having a preset angle.

[0081] like Figure 4 (n) in Figure 4 (o) in Figure 4 (r) and Figure 4 As shown in (s), the first contour edge formed by a plurality of sequentially adjacent first contour points in the coupled grating may include a contour edge with curvature.

[0082] In a coupled grating, if the first contour edge formed by a plurality of sequentially adjacent first contour points includes at least one of the following: a contour edge that is not parallel to the horizontal direction and not parallel to the vertical direction; a contour edge that is partially parallel to the horizontal direction and partially parallel to the vertical direction; a contour edge with a preset angle; or a contour edge with an arc, it can be determined that the first contour edge in the coupled grating does not coincide with the edge of the smallest circumscribed rectangle of the coupled grating, that is, the first contour edge of the coupled grating will deviate from the edge of the smallest circumscribed rectangle of the coupled grating. As the degree of deviation between the first contour edge of the coupled grating and the edge of the smallest circumscribed rectangle of the coupled grating increases, the area difference between the coupled grating and the smallest circumscribed rectangle of the coupled grating will also increase accordingly. Correspondingly, the area difference between the coupling grating and the minimum circumscribed rectangle of the coupling grating can still be limited by the maximum horizontal and maximum vertical dimensions of the minimum circumscribed rectangle of the coupling grating. This ensures that the horizontal distance between the contour points on any two contour sides of the coupling grating is less than or equal to the maximum horizontal dimension of the minimum circumscribed rectangle, and the vertical distance between the contour points on any two contour sides of the coupling grating is less than or equal to the maximum vertical dimension of the minimum circumscribed rectangle. This allows the coupling grating to reduce the light intensity of the rainbow pattern while ensuring the optical display effect of the optical waveguide.

[0083] In one embodiment, the preset shape includes one of polygons, circles, ellipses, and irregular shapes.

[0084] like Figure 2 (a) to Figure 2 (c) Figure 4 (a) to Figure 4 (m) and Figure 4 (p) to Figure 4 As shown in (q), the preset shapes include polygons.

[0085] For example, polygons include one of triangles, quadrilaterals, pentagons, hexagons, heptagons, octagons, dodecagons, hexagons, and icosagons.

[0086] like Figure 2 As shown in (c), the preset shapes include quadrilaterals, such as rhombuses. Figure 4 (a) to Figure 4 As shown in (d) above, the preset shapes include pentagons. Figure 4 (e) to Figure 4 As shown in (h), the preset shapes include hexagons. Figure 4 (i) to Figure 4 (in) l As shown in the image, the preset shapes include heptagons. Figure 2 (a) and Figure 2As shown in (b) therein, the preset shape includes an octagon. As Figure 4 As shown in (m) therein, the preset shape includes a dodecagon. As Figure 4 As shown in (q) therein, the preset shape includes a hexadecagon. As Figure 4 As shown in (p) therein, the preset shape includes an icosagon.

[0087] As Figure 4 As shown in (o) therein, the preset shape includes an ellipse. Accordingly, the preset shape may also include a circle.

[0088] The preset shape may include an irregular shape. The irregular shape may include a shape similar to a preset glyph. Exemplarily, the preset glyph may include "十", "X", "Y", "K", "L", "M", "N", "E", "F", "凹", "凸", "王", etc. Accordingly, the irregular shape may be presented as a shape similar to the preset glyphs such as "十", "X", "Y", "K", "L", "M", "N", "E", "F", "凹", "凸", "王", etc. In an exemplary embodiment, when the irregular shape includes a shape similar to a preset glyph, the irregular shape is, for example, as Figure 4 shown in (m) therein, Figure 4 shown in (n) therein, and Figure 4 shown in (p) to Figure 4 shown in (r) therein. The irregular shape may also include a shape not similar to a preset glyph. The shape not similar to a preset glyph has no any rule, for example, as Figure 4 shown in (s) therein. Of course, the irregular shape is not limited thereto and is not restricted herein.

[0089] When the preset shape includes one of a polygon, a circle, an ellipse, and an irregular shape, it can be ensured that the distance between the contour points on any two contour edges of the coupled grating in the horizontal direction is less than or equal to the maximum horizontal dimension of the minimum circumscribed rectangle, and the distance between the contour points on any two contour edges of the coupled grating in the vertical direction is less than or equal to the maximum vertical dimension of the minimum circumscribed rectangle, so that while the coupled grating can weaken the light intensity of the rainbow pattern for the optical waveguide, the optical display effect of the optical waveguide is guaranteed.

[0090] The optical waveguide provided in the above embodiments, by setting an output grating on the light output region of the optical waveguide, includes multiple contour edges connected end-to-end to form a preset shape of the output grating. The output grating has a minimum circumscribed rectangle, which is different from the preset shape. The distance between contour points on any two contour edges of the output grating in the horizontal direction is less than or equal to the maximum horizontal dimension of the minimum circumscribed rectangle, and the distance between contour points on any two contour edges of the output grating in the vertical direction is less than or equal to the maximum vertical dimension of the minimum circumscribed rectangle. This allows the area of ​​the output grating to be smaller than the area of ​​the minimum circumscribed rectangle, while simultaneously having a maximum dimension in both the horizontal and vertical directions. When the area of ​​the output grating is smaller than the area of ​​the minimum circumscribed rectangle, the amount of light that can be incident on the output grating from outside the waveguide substrate is reduced compared to the minimum circumscribed rectangle, which helps to weaken the intensity of the rainbow effect. When the coupling grating has a maximum size in both the horizontal and vertical directions, the optical display effect of the waveguide can be maintained while reducing the light intensity of the rainbow pattern. This achieves a balance between the optical display effect of the waveguide and the light intensity of the rainbow pattern, ensuring a balance between the optical display effect and the visual effect of the waveguide. This reduces the impact of the rainbow pattern on the user, allowing the waveguide to display images normally and improving the user experience of near-eye display devices equipped with the waveguide.

[0091] Please see Figure 5 , Figure 5 This is a schematic diagram of the structure of a near-eye display device provided in an embodiment of this application.

[0092] In one embodiment, the near-eye display device includes an optical engine and an optical waveguide as provided in any of the embodiments above. The light-coupled region of the optical waveguide is used to couple the light emitted from the optical engine into the waveguide substrate of the optical waveguide, and to couple the light propagating in the waveguide substrate to the human eye through the light-coupled region of the optical waveguide.

[0093] It should be understood that, in any of the embodiments described above, the optical waveguide can couple the light emitted from the optical engine into the waveguide substrate through a light coupling region provided on the waveguide substrate. Then, by utilizing a coupling grating in the light coupling region provided on the waveguide substrate, the light propagating within the waveguide substrate through total internal reflection is diffracted and coupled out, allowing the user to see the image displayed within the optical waveguide. Correspondingly, the coupling grating can also diffract the light generated by light illuminating the outside of the waveguide substrate to the outside of the waveguide substrate. Furthermore, by utilizing the area difference between the smallest circumscribed rectangles of the coupling gratings, the intensity of the rainbow pattern that the user's eye can observe is reduced while maintaining the optical display effect of the optical waveguide. This achieves a balance between the optical display effect of the optical waveguide and the intensity of the rainbow pattern, ensuring a balance between the optical display effect and the visual effect of the optical waveguide. This reduces the impact of the rainbow pattern on the user, allowing the optical waveguide to display images normally and improving the user experience of near-eye display devices equipped with the optical waveguide. The specific structure and implementation principle of the optical waveguide can be found above and will not be described further here.

[0094] For example, near-eye display devices include AR devices, such as AR glasses, AR helmets, etc.; near-eye display devices may also include mixed reality (MR) devices, such as MR glasses, MR helmets, etc., without limitation.

[0095] It should be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0096] It should also be understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. It should be noted that, herein, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0097] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. The above descriptions are merely specific implementations of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An optical waveguide, characterized by, The optical waveguide includes a light coupling region and a waveguide substrate; the light coupling region is disposed on the waveguide substrate; a coupling grating is disposed on the light coupling region; the coupling grating is used to couple light propagating within the waveguide substrate out of the waveguide substrate, and to couple light irradiated from outside the waveguide substrate to the coupling grating out of the waveguide substrate. The coupling grating includes multiple contour edges connected end to end in sequence to form a preset shape of the coupling grating; the coupling grating has a minimum external rectangle, and the minimum external rectangle is different from the preset shape; The horizontal distance between contour points on any two contour edges of the coupled grating is less than or equal to the maximum horizontal dimension of the minimum circumscribed rectangle, and the vertical distance between contour points on any two contour edges of the coupled grating is less than or equal to the maximum vertical dimension of the minimum circumscribed rectangle.

2. The optical waveguide of claim 1, wherein, The contour points of the coupled grating include a first contour point and a second contour point; The horizontal distance between a first contour point on any one contour edge of the coupled grating and a second contour point on another contour edge is less than the maximum horizontal dimension of the minimum external rectangle, and the vertical distance between a first contour point on any one contour edge of the coupled grating and a second contour point on another contour edge is less than the maximum vertical dimension of the minimum external rectangle. The distance between the second contour points on at least two contour edges of the coupled grating in the horizontal direction is equal to the maximum horizontal dimension of the minimum circumscribed rectangle, and the distance between the second contour points on at least two contour edges of the coupled grating in the vertical direction is equal to the maximum vertical dimension of the minimum circumscribed rectangle.

3. The optical waveguide of claim 2, wherein, The horizontal projection size of the first contour edge formed by a plurality of sequentially adjacent first contour points in the coupled grating is less than or equal to the maximum horizontal size of the minimum circumscribed rectangle. The vertical projection size of the first contour edge formed by a plurality of sequentially adjacent first contour points in the coupled grating is less than or equal to the maximum vertical size of the minimum circumscribed rectangle.

4. The optical waveguide of claim 3, wherein, When there are at least two first contour edges, and every two adjacent first contour edges intersect at the same second contour point, the horizontal projection size of the at least two first contour edges in the horizontal direction is less than or equal to the maximum horizontal size of the minimum circumscribed rectangle, and the vertical projection size of the at least two first contour edges in the vertical direction is less than or equal to the maximum vertical size of the minimum circumscribed rectangle.

5. The optical waveguide of claim 3, wherein, The horizontal projection size is greater than or equal to 1 / 7 of the maximum horizontal size of the minimum circumscribed rectangle, and less than or equal to the maximum horizontal size of the minimum circumscribed rectangle; The vertical projection size is greater than or equal to 1 / 7 of the maximum vertical size of the minimum circumscribed rectangle, and less than or equal to the maximum horizontal size of the minimum circumscribed rectangle.

6. The optical waveguide of claim 2, wherein, The first contour edge formed by a plurality of sequentially adjacent second contour points in the coupling grating is recessed toward the center of the coupling grating relative to the second contour edge formed by a plurality of sequentially adjacent first contour points in the coupling grating.

7. The optical waveguide of claim 2, wherein, The first contour edge formed by a plurality of sequentially adjacent first contour points in the output grating includes at least one of a contour edge that is not parallel to the horizontal direction and not parallel to the vertical direction, a contour edge that is partially parallel to the horizontal direction and partially parallel to the vertical direction, a contour edge with a preset angle, and a contour edge with a curvature.

8. The optical waveguide of any of claims 1-7, wherein, The preset shape includes one of a polygon, a circle, an ellipse, and an irregular shape; the irregular shape includes a shape presented as a preset glyph, and the preset glyph includes one of "十", "X", "Y", "K", "L", "M", "N", "E", "F", "凹", "凸", "王".

9. The optical waveguide of claim 8, wherein, The polygon includes one of a triangle, a quadrilateral, a pentagon, a hexagon, a heptagon, an octagon, a dodecagon, a hexadecagon, and an icosagon.

10. A near-eye display device, comprising: The near-eye display device includes an optical engine and an optical waveguide as described in any one of claims 1-9; the optical engine is configured to provide light to the optical waveguide; and the light coupling-out region of the optical waveguide couples out the light propagating in the waveguide substrate of the optical waveguide to the human eye.

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