Optical waveguide and display device

Abstract

The invention discloses an optical waveguide and a display device, the optical waveguide is provided with an entrance pupil area and an exit pupil area, the exit pupil area comprises at least three types of exit pupil sub-areas, each type of exit pupil sub-area comprises at least one exit pupil sub-area, and the grating directions of all types of exit pupil sub-areas are different from each other; input light is diffracted into conduction light through the entrance pupil area, and the conduction light is diffracted into output light through the exit pupil area. The exit pupil area comprises at least three types of exit pupil sub-areas, each type of exit pupil sub-area comprises at least one exit pupil sub-area, and the grating directions of all types of exit pupil sub-areas are different from one another, so that the exit pupil area can be subjected to pupil expansion in multiple dimensions, the size of a display image is increased, and the display efficiency is improved. Meanwhile, the area of the optical waveguide can be reduced, so that the size of the display equipment is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of optical waveguides, and in particular to an optical waveguide and a display device. Background Art

[0002] As a key component in optical devices, optical waveguides play a vital role in display devices such as AR (Augmented Reality) and VR (Virtual Reality). In these display devices, optical waveguides are not only responsible for efficiently guiding the light emitted by the light engine to the exit pupil area near the user's eyes, but also for achieving precise control and optimization of light through their internal structure, so that users can see clear images.

[0003] At present, most mainstream optical waveguides on the market adopt a three-section structure, which consists of an entrance pupil area, an expansion pupil area, and an exit pupil area. The entrance pupil area is responsible for coupling the input light into the optical waveguide, and the expansion pupil area expands the light inside the optical waveguide through a grating to cover a larger field of view. The exit pupil area is responsible for guiding the light passing through the expansion pupil area out of the optical waveguide and finally passing it to the user's eyes. Although this three-section structure can effectively expand the field of view, since each area needs to occupy a certain space, the volume of the entire optical waveguide device is large, which is not conducive to the lightweight and miniaturized design of AR / VR display devices. In order to solve this problem, a two-section optical waveguide has also appeared on the market. The two-section optical waveguide omits the expansion pupil area and only includes the entrance pupil area and the exit pupil area, which can significantly reduce the overall area of ​​the optical waveguide.

[0004] However, the existing two-segment optical waveguide can only expand the pupil in one dimension, resulting in a smaller displayed image and a larger display device. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present application provides an optical waveguide and a display device, wherein the exit pupil area includes at least three types of exit pupil sub-areas, each type of exit pupil sub-areas includes at least one exit pupil sub-area, and the grating directions of each type of exit pupil sub-areas are different. The exit pupil area can be expanded in multiple dimensions, thereby increasing the size of the displayed image, and at the same time, the area of ​​the optical waveguide can be reduced, thereby reducing the volume of the display device.

[0006] To solve the above problems, the present invention provides the following technical solutions:

[0007] In a first aspect, an embodiment of the present application provides an optical waveguide, wherein an entrance pupil region and an exit pupil region are provided on the optical waveguide, wherein the exit pupil region includes at least three types of exit pupil sub-regions, each type of exit pupil sub-region includes at least one exit pupil sub-region, and the grating directions of each type of exit pupil sub-region are different from each other;

[0008] The input light is diffracted through the entrance pupil area to form the transmission light, and the transmission light is diffracted through the exit pupil area to form the output light.

[0009] In some embodiments, the exit pupil area includes a first type of exit pupil sub-area, a second type of exit pupil sub-area, and a third type of exit pupil sub-area. The first angle between the first grating direction of the first type of exit pupil sub-area and the second grating direction of the second type of exit pupil sub-area is in a range of 20 degrees to 80 degrees, the second angle between the first grating direction and the third grating direction of the third type of exit pupil sub-area is in a range of 20 degrees to 80 degrees, and the third angle between the second grating direction and the third grating direction is in a range of 40 degrees to 160 degrees.

[0010] In some embodiments, the area of ​​each of the exit pupil sub-regions is the same.

[0011] In some embodiments, each of the exit pupil sub-areas is an equilateral hexagonal area.

[0012] In some embodiments, the grating direction of the entrance pupil area is different from the grating direction of each type of exit pupil sub-area; or

[0013] The grating direction of one type of exit pupil sub-area is the same as the grating direction of the entrance pupil area.

[0014] In some embodiments, the total area of ​​each type of exit pupil sub-region is the same; or

[0015] The total areas of at least two types of exit pupil sub-regions are different.

[0016] In some embodiments, in the exit pupil region, there is an exit pupil sub-region whose grating direction is different from that of all adjacent exit pupil sub-regions.

[0017] In some embodiments, the optical waveguide includes one entrance pupil region and two exit pupil regions.

[0018] In some embodiments, the optical waveguide includes two entrance pupil areas and one exit pupil area, and the two entrance pupil areas are symmetrically arranged on both sides of the exit pupil area.

[0019] In a second aspect, an embodiment of the present application provides a display device, comprising an optical machine and an optical waveguide as described in the first aspect, wherein the optical machine is used to project input light into an entrance pupil area.

[0020] The present application provides an optical waveguide and a display device. The present application includes at least three types of exit pupil sub-regions in an exit pupil area, each type of exit pupil sub-region includes at least one exit pupil sub-region, and the grating directions of each type of exit pupil sub-region are different from each other. The exit pupil area can be expanded in multiple dimensions, thereby increasing the size of the displayed image, and at the same time can reduce the area of ​​the optical waveguide, thereby reducing the volume of the display device. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic structural diagram of a first implementation mode of an optical waveguide provided in an embodiment of the present application.

[0022] Figure 2 yes Figure 1 Magnified view of area A1 in the middle.

[0023] Figure 3 It is a schematic structural diagram of a second implementation of the optical waveguide provided in an embodiment of the present application.

[0024] Figure 4 It is a schematic structural diagram of a third implementation mode of the optical waveguide provided in an embodiment of the present application.

[0025] Figure 5 It is a schematic structural diagram of a fourth implementation mode of an optical waveguide provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0027] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0028] The terms such as "symmetry" or "axisymmetry" mentioned in the technical solution of the present invention are intended to describe an ideal state, and it may be difficult to achieve absolute symmetry in actual operation. Here, it is particularly noted that the terms such as "symmetry" or "axisymmetry" refer to an object or structure that is as close to a symmetrical state as possible in terms of shape, size, performance, etc. within the scope that can be achieved by those skilled in the art. In practical applications, due to the limitations of manufacturing processes, material properties and other factors, absolute symmetry cannot be achieved. The terms such as "symmetry" or "axisymmetry" mentioned in the technical solution of the present invention refer to being as close to a symmetrical state as possible, so as to achieve the predetermined technical effects and performance requirements.

[0029] The present application provides an optical waveguide and a display device, wherein an exit pupil area includes at least three types of exit pupil sub-areas, each type of exit pupil sub-areas includes at least one exit pupil sub-area, and the grating directions of each type of exit pupil sub-areas are different from each other, so that the exit pupil area can be expanded in multiple dimensions, thereby increasing the size of the displayed image, and at the same time, the area of ​​the optical waveguide can be reduced, thereby reducing the volume of the display device.

[0030] The optical waveguide provided by the present application will be described in detail below with reference to the accompanying drawings.

[0031] See also Figure 1 , Figure 1 Schematic diagram of the structure of the first embodiment of the optical waveguide provided in the embodiment of the present application. Figure 1 As shown, in some embodiments, an entrance pupil region 10 and an exit pupil region 20 are provided on the optical waveguide 1, and the exit pupil region 20 includes at least three types of exit pupil sub-regions, each type of exit pupil sub-region includes at least one exit pupil sub-region, and the grating directions of each type of exit pupil sub-region are different from each other. The input light is diffracted into the conductive light through the entrance pupil region, and the conductive light is diffracted into the output light through the exit pupil region. In this way, the exit pupil region can be expanded in multiple dimensions, thereby increasing the size of the displayed image, and at the same time, the area of ​​the optical waveguide can be reduced, thereby reducing the volume of the display device.

[0032] Optionally, the total number of exit pupil sub-areas included in the exit pupil area 20 is greater than 3, for example, 3, 5, 10, 50 or 100.

[0033] In some embodiments, the exit pupil area 20 includes a first type of exit pupil sub-area 21 , a second type of exit pupil sub-area 22 , and a third type of exit pupil sub-area 23 . Figure 1 The line segments in the entrance pupil region 10, the first type of exit pupil sub-region 21, the second type of exit pupil sub-region 22 and the third type of exit pupil sub-region 23 all represent gratings. Figure 1 Other exit pupil sub-regions (such as exit pupil sub-region 24) in FIG. 1 are also provided with gratings, but only in Figure 1 Not shown in the figure for the sake of simplicity.

[0034] See also Figure 2 , Figure 2 yes Figure 1 A magnified view of area A1 in the middle. Figure 2 As shown, in some embodiments, the first angle J1 between the first grating direction R1 of the first type of exit pupil sub-region 21 and the second grating direction R2 of the second type of exit pupil sub-region 22 is in the range of 20 degrees to 80 degrees, for example, the first angle J1 is 20 degrees, 30 degrees, 40 degrees, 50 degrees, 60 degrees, 70 degrees or 80 degrees. The second angle J2 between the first grating direction R1 and the third grating direction R3 of the third type of exit pupil sub-region 23 is in the range of 20 degrees to 80 degrees, for example, the second angle J2 is 20 degrees, 30 degrees, 40 degrees, 50 degrees, 60 degrees, 70 degrees or 80 degrees. The third angle J3 between the second grating direction R2 and the third grating direction R3 is in the range of 40 degrees to 160 degrees, for example, the third angle J3 is 40 degrees, 60 degrees, 90 degrees, 100 degrees, 150 degrees or 160 degrees.

[0035] Optionally, the first angle J1 is 60 degrees, the second angle J2 is 60 degrees, and the third angle J3 is 120 degrees.

[0036] It can be understood that the first grating direction R1, the second grating direction R2, the third grating direction R3, the first angle J1, the second angle J2 and the third angle J3 are mathematical terms used only to describe the structure of the optical waveguide 1, and are not actual structures on the optical waveguide 1.

[0037] In some embodiments, the area of ​​each exit pupil sub-region is the same. In this way, the area of ​​each exit pupil sub-region receiving light is the same, which can improve the uniformity of the brightness of the displayed image.

[0038] Furthermore, the boundaries of each exit pupil sub-area are strictly aligned. In this way, the brightness uniformity of the displayed image can be further improved.

[0039] Furthermore, each exit pupil sub-region is a plane tessellation figure. The plane tessellation figure is used to realize plane tessellation. Plane tessellation refers to using multiple congruent plane tessellation figures to completely cover a plane without leaving any gaps.

[0040] Optionally, each exit pupil sub-area is an equilateral hexagonal area. In this way, the equilateral hexagonal area can provide similar optical path lengths in multiple directions, thereby reducing the phase difference between different paths, avoiding the screen ratio of the displayed image not meeting the preset ratio, and improving the uniformity of the brightness of the displayed image. In addition, compared with other geometric shapes such as squares or circles, equilateral hexagons can more effectively fill planes and reduce gaps, thereby reducing the waste of light energy and improving the brightness of displayed images.

[0041] Optionally, the shape of the exit pupil sub-area may also be any shape such as a rectangle, a circle, a sector or an irregular shape, which is not limited here.

[0042] Optionally, the shape of the exit pupil area 20 may be any shape such as a rectangle, a circle, a sector or an irregular shape, which is not limited here.

[0043] In some embodiments, the area of ​​each exit pupil sub-region is the same, and each exit pupil sub-region is an equilateral hexagonal region.

[0044] In some embodiments, the grating of each type of exit pupil sub-region is a one-dimensional grating. A one-dimensional grating has a higher diffraction efficiency and is less difficult to produce in terms of process.

[0045] Optionally, the optical parameters of the gratings in each exit pupil sub-area are the same. The optical parameters include parameters such as grating depth and grating period. In this way, it is possible to further avoid the screen ratio of the displayed image not meeting the preset ratio and improve the brightness uniformity of the displayed image.

[0046] Furthermore, the gratings of each type of exit pupil sub-area are on the same surface of the optical waveguide.

[0047] Optionally, the boundaries of each exit pupil sub-area may not be strictly aligned. In this case, the grating of each exit pupil sub-area is a one-dimensional grating. Compared with the strict alignment of each exit pupil sub-area or the strict symmetry of the grating directions of the first exit pupil sub-area and the second exit pupil sub-area, this implementation method has a lower production difficulty in terms of process and does not significantly change the imaging effect.

[0048] like Figure 1 As shown, in some embodiments, the grating direction of the entrance pupil area 10 is different from the grating direction of each type of exit pupil sub-area. At this time, the input light is diffracted into the transmission light through the entrance pupil area 10, and the transmission light forms the output light after undergoing at least two diffractions in the exit pupil area 20. In this way, the exit pupil area can be expanded in more dimensions, thereby further increasing the size of the displayed image, and at the same time, the area of ​​the optical waveguide can be reduced, thereby reducing the volume of the display device.

[0049] Taking the optical path of the first type of exit pupil sub-region 21 as an example, part of the conducted light is diffracted by the first type of exit pupil sub-region 21 and then emitted to the second type of exit pupil sub-region 22, and then diffracted by the second type of exit pupil sub-region 22 to form the first output light; part of the conducted light is diffracted by the first type of exit pupil sub-region 21 and then emitted to the second type of exit pupil sub-region 22, and then diffracted by the second type of exit pupil sub-region 22 and then emitted to the third type of exit pupil sub-region 23 to form the second output light. The optical paths of the second exit pupil sub-region 22 and the third type of exit pupil sub-region 23 refer to the optical path of the first type of exit pupil sub-region 21.

[0050] See also Figure 3 , Figure 3 Schematic diagram of the structure of the second embodiment of the optical waveguide provided in the embodiment of the present application. Figure 3 As shown, in other embodiments, the grating direction of one type of exit pupil sub-region 25 is the same as the grating direction of the entrance pupil region 10. At this time, part of the transmitted light is diffracted by one type of exit pupil sub-region 25 to form a third output light. Part of the transmitted light is diffracted by one type of exit pupil sub-region 25 and emitted to other types of exit pupil sub-regions, and then diffracted by other types of exit pupil sub-regions to form a fourth output light. The specific optical path refers to the above description. In this way, part of the transmitted light can be diffracted only once by one type of exit pupil sub-region 25 to form the third output light, and then form a display image. In this way, the light energy lost by coupling out the display image directly is less than that of coupling out the display image after multiple diffractions, thereby expanding the pupil of the exit pupil region 20 in multiple dimensions while also improving the brightness of the display image.

[0051] Optionally, a type of exit pupil sub-region 25 having a grating direction that is the same as that of the entrance pupil region 10 is disposed close to the entrance pupil region 10 .

[0052] It can be understood that the input light enters the entrance pupil area along a direction perpendicular to the plane where the entrance pupil area 10 is located. The output light is emitted from the exit pupil area 20 along a direction perpendicular to the plane where the exit pupil area 20 is located, and then forms a display image at the human eye. The relative position of the entrance pupil area 10 and the exit pupil area 20 is not limited to Figure 1 In the case shown, the entrance pupil area 10 can be located at any position such as the left side, right side, top side or bottom side of the exit pupil area 20, as long as the input light can pass through the entrance pupil area 10 and the exit pupil area 20 to form a display image.

[0053] In some embodiments, the total area of ​​each type of exit pupil sub-region is the same. In this way, each type of exit pupil sub-region receives the same amount of light energy, and the brightness of the corresponding display area in the displayed image is the same, thereby improving the uniformity of the brightness of the displayed image.

[0054] In other embodiments, the total areas of at least two types of exit pupil sub-regions are different. In this way, the display area corresponding to the type of exit pupil sub-region with a larger area in the displayed image will be brighter, which can meet the usage requirements of different users.

[0055] Optionally, in the exit pupil region, there is an exit pupil sub-region whose grating direction is different from that of all adjacent exit pupil sub-regions. In this way, the guided light can be more fully diffracted in the exit pupil region (the number of diffractions increases), so that the exit pupil region is expanded in more dimensions, thereby increasing the size of the displayed image, and at the same time, the area of ​​the optical waveguide can be reduced, thereby reducing the volume of the display device.

[0056] For example, Figure 3 As shown, when each exit pupil sub-region is an equilateral hexagonal region, there are 6 exit pupil sub-regions adjacent to one exit pupil sub-region. There is at least one exit pupil sub-region, and the grating direction of the exit pupil sub-region is different from the grating direction of each adjacent exit pupil sub-region.

[0057] Optionally, the shape, area and grating direction of each exit pupil sub-region in the target region are set according to the brightness of the display region in the display image corresponding to the target region in the exit pupil region.

[0058] For example, in the edge region of the light guide, each exit pupil sub-region has a different grating direction from all adjacent exit pupil sub-regions. The display region in the display image corresponding to the edge region is usually darker. In this way, the brightness of the display region corresponding to the edge region can be increased, thereby improving the uniformity of the brightness of the display image.

[0059] See also Figure 4 , Figure 4 is a schematic structural diagram of a third embodiment of the optical waveguide provided in the embodiment of the present application. Figure 4 As shown, in some embodiments, the optical waveguide 1 includes an entrance pupil area 10 and two exit pupil areas 20. For the description of the exit pupil area 20, refer to the above content. At this time, the optical waveguide 1 is a binocular waveguide, which has a larger field of view than a monocular waveguide.

[0060] Optionally, two exit pupil areas 20 are symmetrically arranged on both sides of the entrance pupil area 10 .

[0061] Optionally, the grating directions of the two exit pupil regions 20 are also symmetrical.

[0062] Furthermore, the optical parameters of the gratings of the two exit pupil regions 20 are the same.

[0063] Optionally, the shape of the entrance pupil area is circular, rectangular, fan-shaped, etc.

[0064] Because the light spot of the output light from the optical machine is generally a circular spot, such as Figure 4 As shown, preferably, the shape of the entrance pupil area 10 is circular. In this way, the entrance pupil area can receive as much output light as possible, while reducing the area of ​​the entrance pupil area, thereby reducing the manufacturing cost.

[0065] It is understandable that the relative position of the entrance pupil area 10 and the exit pupil area 20 is not limited to Figure 4 In the case shown, the entrance pupil area 10 can be located at any position such as the left side, right side, top side or bottom side of the exit pupil area 20, as long as the input light can pass through the entrance pupil area 10 and the exit pupil area 20 to form a display image.

[0066] See also Figure 5 , Figure 5 Schematic diagram of the structure of the fourth embodiment of the optical waveguide provided in the embodiment of the present application. Figure 5 As shown, in some embodiments, the optical waveguide 1 includes two entrance pupil areas 10 and one exit pupil area 20, and the two entrance pupil areas 10 are symmetrically arranged on both sides of the exit pupil area 20. In this case, the optical waveguide 1 is an integrated optical waveguide.

[0067] It is understandable that the relative position of the entrance pupil area 10 and the exit pupil area 20 is not limited to Figure 5 In the case shown, the entrance pupil area 10 can be located at any position such as the left side, right side, top side or bottom side of the exit pupil area 20, as long as the input light can pass through the entrance pupil area 10 and the exit pupil area 20 to form a display image.

[0068] In summary, the optical waveguide provided in the embodiments of the present application has the following advantages:

[0069] 1. The exit pupil area includes at least three types of exit pupil sub-areas, each type of exit pupil sub-areas includes at least one exit pupil sub-area, and the grating directions of each type of exit pupil sub-areas are different from each other, so that the exit pupil area can be expanded in multiple dimensions, thereby increasing the size of the displayed image, and at the same time can reduce the area of ​​the optical waveguide, thereby reducing the volume of the display device.

[0070] 2. By making the area of ​​each exit pupil sub-region the same, the area of ​​each exit pupil sub-region receiving light is the same, which can improve the uniformity of the brightness of the displayed image.

[0071] 3. By making each exit pupil sub-area an equilateral hexagonal area, the equilateral hexagonal area can provide similar optical path lengths in multiple directions, thereby reducing the phase difference between different paths, avoiding the screen ratio of the displayed image not meeting the preset ratio, and improving the uniformity of the brightness of the displayed image. In addition, compared with other geometric shapes such as squares or circles, equilateral hexagons can fill planes more effectively and reduce gaps, thereby reducing the waste of light energy and improving the brightness of displayed images.

[0072] 4. By making the grating direction of the entrance pupil area different from the grating direction of each type of exit pupil sub-area, the guided light can be more fully diffracted in the exit pupil area (increasing the number of diffraction), so that the exit pupil area can be expanded in more dimensions, thereby increasing the size of the displayed image and at the same time reducing the area of ​​the optical waveguide, thereby reducing the volume of the display device.

[0073] 5. By making the grating direction of one type of exit pupil sub-area the same as the grating direction of the entrance pupil area, part of the transmitted light can be diffracted only once by one type of exit pupil sub-area to form the third output light, and then form a display image. In this way, the light energy lost by directly coupling out the display image is less than that of coupling out the display image after multiple diffractions, thereby expanding the exit pupil area in more dimensions and improving the brightness of the display image.

[0074] The present application also provides a display device, including an optical machine and the optical waveguide as described above, wherein the optical machine is used to project input light to an entrance pupil area.

[0075] Optionally, the display device may be an AR display device or a VR display device.

[0076] In summary, the present application provides an optical waveguide and a display device, wherein an entrance pupil region and an exit pupil region are provided on the optical waveguide, wherein the exit pupil region includes at least three types of exit pupil sub-regions, each type of exit pupil sub-region includes at least one exit pupil sub-region, and the grating directions of each type of exit pupil sub-region are different from each other; input light is diffracted through the entrance pupil region to form transmission light, and the transmission light is diffracted through the exit pupil region to form output light. The present application enables the exit pupil region to be expanded in more dimensions by including at least three types of exit pupil sub-regions in the exit pupil region, each type of exit pupil sub-region includes at least one exit pupil sub-region, and the grating directions of each type of exit pupil sub-region are different from each other, thereby increasing the size of the displayed image, and at the same time reducing the area of ​​the optical waveguide, thereby reducing the volume of the display device.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An optical waveguide, characterized in that: The optical waveguide is provided with an entrance pupil area and an exit pupil area, the exit pupil area includes at least three types of exit pupil sub-areas, each type of exit pupil sub-area includes at least one exit pupil sub-area, and the grating directions of each type of exit pupil sub-area are different from each other; The input light is diffracted through the entrance pupil area to form the transmission light, and the transmission light is diffracted through the exit pupil area to form the output light.

2. The optical waveguide according to claim 1, characterized in that The exit pupil area includes a first type of exit pupil sub-area, a second type of exit pupil sub-area and a third type of exit pupil sub-area. The first angle between the first grating direction of the first type of exit pupil sub-area and the second grating direction of the second type of exit pupil sub-area is in a range of 20 degrees to 80 degrees, the second angle between the first grating direction and the third grating direction of the third type of exit pupil sub-area is in a range of 20 degrees to 80 degrees, and the third angle between the second grating direction and the third grating direction is in a range of 40 degrees to 160 degrees.

3. The optical waveguide according to claim 1, characterized in that The area of ​​each exit pupil sub-region is the same.

4. The optical waveguide according to claim 3, characterized in that Each of the exit pupil sub-areas is an equilateral hexagonal area.

5. The optical waveguide according to claim 1, characterized in that The grating direction of the entrance pupil area is different from the grating direction of each type of exit pupil sub-area; or The grating direction of one type of exit pupil sub-area is the same as the grating direction of the entrance pupil area.

6. The optical waveguide according to claim 1, characterized in that The total area of ​​each type of exit pupil sub-region is the same; or The total areas of at least two types of exit pupil sub-regions are different.

7. The optical waveguide according to claim 1, characterized in that In the exit pupil region, there is an exit pupil sub-region having a grating direction different from all adjacent exit pupil sub-regions.

8. The optical waveguide according to any one of claims 1 to 7, characterized in that: The optical waveguide includes one entrance pupil area and two exit pupil areas.

9. The optical waveguide according to any one of claims 1 to 7, characterized in that: The optical waveguide includes two entrance pupil areas and one exit pupil area, and the two entrance pupil areas are symmetrically arranged on both sides of the exit pupil area.

10. A display device, characterized in that: The display device comprises an optical engine and the optical waveguide according to any one of claims 1 to 9, wherein the optical engine is used to project input light to an entrance pupil area.

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