Grating waveguide, augmented reality device, virtual reality device and mixed reality device

Abstract

The utility model is applicable to the technical field of augmented reality, and provides a grating waveguide, augmented reality equipment, virtual reality equipment and mixed reality device.The grating waveguide comprises a first coupling-out element, a second coupling-out element, a coupling-in element, a first waveguide substrate, a scattering element and a second waveguide substrate, and the coupling-in element, the first waveguide substrate, the scattering element and the second waveguide substrate are sequentially stacked; the coupling-in element and the first coupling-out element are arranged on the first waveguide substrate at an interval, the second coupling-out element is arranged on the second waveguide substrate, and the orthographic projection area of the second coupling-out element on the first waveguide substrate deviates from the first coupling-out element; the first image light enters the first waveguide substrate through the coupling element to form second image light; the second image light is transmitted to the scattering element through the first waveguide substrate and forms blurred image light after being scattered by the scattering element, and the blurred image light is transmitted to the second coupling-out element through the second waveguide substrate and is emitted to the world side through the second coupling-out element. According to the embodiment of the invention, user privacy leakage can be prevented.

Description

Technical Field

[0001] This application belongs to the field of extended reality (XR) technology, and particularly relates to diffractive waveguides and augmented reality devices, virtual reality devices and mixed reality devices. Background Technology

[0002] In extended reality technology, grating waveguides are a key optical component, widely used in augmented reality (AR), virtual reality (VR), and mixed reality (MR) devices. Image light emitted by the opto-mechanical system enters the waveguide substrate through a coupling-in element. Within the waveguide substrate, it propagates via total internal reflection (TIR) ​​and is diffracted into two parts by a coupling-out element. One part of the image light is projected onto the user's eye, while the other part is projected onto the world side, away from the user, potentially leading to privacy breaches. Utility Model Content

[0003] In view of this, embodiments of this application provide a grating waveguide and augmented reality device, virtual reality device and mixed reality device, which can prevent the leakage of user privacy.

[0004] A first aspect of this application provides a grating waveguide, including a first coupling element, a second coupling element, and a coupling element, a first waveguide substrate, a scattering element, and a second waveguide substrate stacked sequentially, wherein the first waveguide substrate is located on the user side, the second waveguide substrate is located on the world side, the coupling element and the first coupling element are spaced apart on the first waveguide substrate, the second coupling element is located on the second waveguide substrate, and the orthographic projection area of ​​the second coupling element on the first waveguide substrate is offset from the first coupling element;

[0005] The first image light enters the first waveguide substrate through the coupling element, forming the second image light and the third image light;

[0006] The second image light propagates through the first waveguide substrate to the scattering element, and after being scattered by the scattering element, it forms blurred image light and enters the second waveguide substrate;

[0007] The blurred image light propagates through the second waveguide substrate to the second coupling element, and is emitted to the world side through the second coupling element;

[0008] The third image light propagates through the first waveguide substrate to the first coupling element, and is diffracted by the first coupling element to form a fourth image light and a fifth image light. The fourth image light is emitted to the user side, and the fifth image light is emitted to the world side.

[0009] The world light from the world side passes through the second waveguide substrate and the first waveguide substrate in sequence and is emitted to the user side.

[0010] The grating waveguide provided in the first aspect of this application allows external first image light to enter the first waveguide substrate via a coupling element, forming a second image light and a third image light. The second image light propagates through the first waveguide substrate to a scattering element, is scattered by the scattering element to form a blurred image light, and then propagates through the second waveguide substrate to a second coupling element, and is emitted to the world side via the second coupling element. The third image light propagates through the first waveguide substrate to the first coupling element, and is diffracted by the first coupling element to form a fourth image light and a fifth image light. The fourth image light is emitted to the user side, and the fifth image light is emitted to the world side. The world light from the world side is emitted to the user side via the first waveguide substrate and the first coupling element in sequence. This allows the blurred image light to be superimposed with a portion of the image light (i.e., the fifth image light) and emitted to the world side, reducing the clarity of this portion of the image light to prevent user privacy leakage. Since the world light and another portion of the image light (i.e., the fourth image light) can be emitted to the user's eye on the user side, it can be applied to augmented reality devices.

[0011] In one embodiment, the scattering element includes at least one of a diffuser sheet, a scattering film, a microlens array, frosted glass, a semi-transparent material layer, and a natural scattering material layer.

[0012] The embodiments of this application scatter the second image light by using at least one of the following: a diffuser sheet, a scattering film, a microlens array, frosted glass, a semi-transparent material layer, and a natural scattering material layer, to form a blurred image light. The structure is simple, easy to implement, and low in cost.

[0013] In one embodiment, the second coupling element is a sawtooth groove region formed in the second waveguide substrate.

[0014] In this embodiment, a sawtooth groove region is directly opened in the second waveguide substrate as the second coupling element, so that the second coupling element and the second waveguide substrate are the same integrated structure, which is easy to assemble with other optical components and can effectively improve the stability of the optical path.

[0015] In one embodiment, the second waveguide substrate is a first light-transmitting cover plate.

[0016] This application embodiment reuses the second waveguide substrate as a light-transmitting cover to protect other optical components, achieving multiple uses with one piece, thereby simplifying the structure and saving costs.

[0017] In one embodiment, the orthogonal projection region of the second coupling element on the first waveguide substrate is located between the coupling element and the first coupling element.

[0018] This embodiment of the application improves the structural compactness of the grating waveguide by placing the orthographic projection area of ​​the second coupling element on the first waveguide substrate between the coupling element and the first coupling element, while satisfying the condition that the orthographic projection area of ​​the second coupling element on the first waveguide substrate is offset from the first coupling element, so as to avoid affecting the entry of world light into the user side.

[0019] In one embodiment, the grating waveguide further includes a second light-transmitting cover plate disposed on the user side.

[0020] The embodiments of this application can protect the coupling element, the first waveguide substrate and the first coupling element by setting a light-transmitting cover on the user side.

[0021] In one embodiment, the coupling element and the first coupling element are disposed on the surface of the first waveguide substrate near the user side.

[0022] The embodiments of this application facilitate fabrication and simplify the fabrication process of the grating waveguide by placing the coupling element and the first coupling element on the same surface of the first waveguide substrate.

[0023] A second aspect of this application provides an augmented reality device, including an optical engine and the grating waveguide described in the first aspect, wherein the first image light is emitted by the optical engine to the coupling element.

[0024] This application embodiment realizes an augmented reality device based on a grating waveguide of the first aspect. By causing blurred image light to be superimposed on image light and emitted to the world side, the clarity of the image light is reduced, which can prevent the leakage of user privacy.

[0025] A third aspect of this application provides a virtual reality device, including an optical engine, a light-shielding element, and the grating waveguide described in the first aspect. The first image light is emitted by the optical engine to the coupling element, and the light-shielding element is disposed in the orthogonal projection area of ​​the first coupling element on the second waveguide substrate to block the fifth image light and the world light.

[0026] This application embodiment adds a light-shielding element to the grating waveguide of the first aspect. Since the light-shielding element can block ambient light from entering the grating waveguide, only image light is emitted to the user's eyes on the user side, thereby realizing a virtual reality device. At the same time, since the light-shielding element can block image light from emitting to the ambient side, only blurred image light is emitted to the ambient side, which can effectively prevent the leakage of user privacy.

[0027] A fourth aspect of this application provides a mixed reality device, including an optical engine, a variable aperture, and a grating waveguide as described in the first aspect. The first image light is emitted by the optical engine to the coupling element, and the variable aperture is disposed in the orthographic projection area of ​​the first coupling element on the second waveguide substrate for adjusting the light transmittance of the fifth image light and the world light.

[0028] This application embodiment adds a variable aperture to the grating waveguide of the first aspect. Since the variable aperture can adjust the amount of image light emitted to the world side and the amount of world light entering the grating waveguide, it can realize augmented reality function when the amount of light is greater than 0 and virtual reality function when the amount of light is equal to 0, thereby realizing mixed reality function. When the amount of light is greater than 0, the display effect of augmented reality function can also be adjusted by adjusting the amount of light. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the first structure of the grating waveguide provided in the embodiments of this application;

[0031] Figure 2 This is a schematic diagram of a second structure of the grating waveguide provided in an embodiment of this application;

[0032] Figure 3 This is a schematic diagram of the third structure of the grating waveguide provided in the embodiments of this application;

[0033] Figure 4 This is a schematic diagram of the fourth structure of the grating waveguide provided in the embodiments of this application;

[0034] Figure 5 This is a schematic diagram of the structure of the augmented reality device provided in the embodiments of this application;

[0035] Figure 6 This is a schematic diagram of the structure of the virtual reality device provided in the embodiments of this application;

[0036] Figure 7 This is a schematic diagram of the structure of the mixed reality device provided in the embodiments of this application;

[0037] Icon labels:

[0038] Grating waveguide-100, coupling element-10, first waveguide substrate-20, first coupling element-30, scattering element-40, second waveguide substrate-50, second coupling element-60, second light-transmitting cover plate-70;

[0039] First image light -101, second image light -102, third image light -103, blurred image light -104, fourth image light -105, fifth image light -106, world light -107;

[0040] Augmented reality equipment - 1000, optical engine - 200;

[0041] Virtual reality equipment - 2000, light-shielding element - 300;

[0042] Mixed Reality Device-3000, Variable Aperture-400. Detailed Implementation

[0043] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present application.

[0044] The term "comprising," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover a non-exclusive inclusion. For example, a process, method, system, product, or apparatus that comprises a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or apparatus. Furthermore, the terms "first," "second," and "third," etc., are used to distinguish different objects, not to describe a specific order.

[0045] like Figures 1-4As shown, this embodiment provides a grating waveguide 100, including a first coupling element 30, a second coupling element 60, and a coupling element 10, a first waveguide substrate 20, a scattering element 40, and a second waveguide substrate 50 stacked sequentially. The first waveguide substrate 20 is located on the user side, and the second waveguide substrate 50 is located on the world side. The coupling element 10 and the first coupling element 30 are spaced apart on the first waveguide substrate 20, and the second coupling element 60 is disposed on the second waveguide substrate 50, with the orthographic projection area of ​​the second coupling element 60 on the first waveguide substrate 20 offset from the first coupling element 30.

[0046] The first image light 101 enters the first waveguide substrate 20 via the coupling element 10 to form the second image light 102 and the third image light 103;

[0047] The second image light 102 propagates through the first waveguide substrate 20 to the scattering element 40, and is scattered by the scattering element 40 to form the blurred image light 104;

[0048] The blurred image light 104 propagates through the second waveguide substrate 50 to the second coupling element 60, and is emitted to the world side through the second coupling element 60;

[0049] The third image light 103 propagates through the first waveguide substrate 20 to the first coupling element 30, and is diffracted by the first coupling element 30 to form the fourth image light 105 and the fifth image light 106. The fourth image light 105 is emitted to the user side.

[0050] The world light 107 on the world side passes through the second waveguide substrate 50 and the first waveguide substrate 20 in sequence and is emitted to the user side.

[0051] In applications, the coupling element 10 can be a lens-type coupling element, prism-type coupling element, or grating-type coupling element composed of lenses (e.g., convex lenses, concave lenses, or aspherical lenses), prisms, gratings (e.g., surface relief gratings or volume holographic gratings), or the coupling element 10 can be an optical fiber coupler or a microlens array. The coupling element 10 is used to efficiently couple the external first image light 101 into the interior of the first waveguide substrate 20. By controlling the incident angle of the first image light 101, the first image light 101 enters the first waveguide substrate 20 and forms a second image light 102 and a third image light 103. The second image light 102 propagates to the scattering element 40, and the third image light 103 satisfies the total internal reflection condition. The second image light 102 is the 0th order diffracted light that leaks out through the first waveguide substrate 20.

[0052] In applications, the first waveguide substrate 20 can be a glass substrate layer, plastic substrate layer, crystalline material substrate layer, or composite material substrate layer made of transparent materials such as glass (e.g., quartz glass, BK7 glass, etc.), plastic (e.g., polymethyl methacrylate (PMMA), polycarbonate (PC), etc.), crystalline material (e.g., sapphire (Al2O3), composite material (e.g., doped or modified glass). The first waveguide substrate 20 serves as a medium for optical signal propagation, allowing the second image light 102 to propagate to the scattering element 40 and causing the third image light 103 to undergo total internal reflection within the first waveguide substrate 20. It also supports the coupling element 10 and the first coupling element 30.

[0053] In applications, the first coupling element 30 can be a grating-type coupling element, a prism-type coupling element, or a mirror-type coupling element composed of a grating (e.g., a surface relief grating or a volume holographic grating), a prism, a mirror (e.g., a micro-mirror), or the first coupling element 30 can be an optical fiber coupler or a microlens array. The first coupling element 30 is used to diffract the third image light 103 propagating inside the first waveguide substrate 20 through total internal reflection to form a fourth image light 105 and a fifth image light 106, and efficiently couples out the fourth image light 105 and projects it to the user side, and efficiently couples out the fifth image light 106 and projects it to the world side.

[0054] In applications, the first coupling element 30 can be disposed on the surface of the first waveguide substrate 20 near the user side or away from the user side. By providing multiple position selection schemes for the first coupling element 30 disposed on the first waveguide substrate 20, the fabrication process of the grating waveguide 100 is made more flexible.

[0055] like Figures 1-4 As shown, in one embodiment, both the coupling element 10 and the first coupling element 30 are disposed on the surface of the first waveguide substrate 20 near the user side. By disposing the coupling element 10 and the first coupling element 30 on the same surface of the first waveguide substrate 20, fabrication is facilitated, and the fabrication process of the grating waveguide 100 is simplified.

[0056] In applications, the scattering element 40 can be implemented using at least one of a diffuser, a scattering film, a microlens array, frosted glass, a semi-transparent material layer, and a natural scattering material layer. By scattering the second image light 102, the light is diffused, thereby forming a blurred image light 104. The clarity of the blurred image light 104 projected onto the world side is lower than the clarity of the virtual image formed by the second image light 102 directly projected onto the world side without passing through the scattering element 40. The structure is simple, easy to implement, and low in cost. When the scattering element 40 is implemented using multiple of the diffuser, scattering film, microlens array, frosted glass, semi-transparent material layer, and natural scattering material layer, these optical elements are stacked sequentially along the light transmission direction.

[0057] In applications, the second waveguide substrate 50 can be a glass substrate layer, plastic substrate layer, crystalline material substrate layer, or composite material substrate layer made of transparent materials such as glass (e.g., quartz glass, BK7 glass, etc.), plastic (e.g., polymethyl methacrylate, polycarbonate, etc.), crystalline material (e.g., sapphire (Al2O3), composite material (e.g., doped or modified glass). The second waveguide substrate 50 serves as the medium for optical signal propagation, causing the blurred image light 104 to undergo total internal reflection within the second waveguide substrate 50 and propagate to the second coupling element 60.

[0058] In one embodiment, the second waveguide substrate 50 is the first light-transmitting cover plate.

[0059] In applications, the second waveguide substrate 50 can be reused as the first light-transmitting cover to protect other optical components, making it a multi-purpose device that simplifies the structure and saves costs.

[0060] In applications, the second coupling element 60 can be a grating-type coupling element, a prism-type coupling element, or a mirror-type coupling element composed of a grating (e.g., a surface relief grating or a volume holographic grating), a prism, a mirror (e.g., a micro-mirror), or, alternatively, an fiber optic coupler or a microlens array. The second coupling element 60 is used to diffract the blurred image light 104 propagating inside the second waveguide substrate 50 via total internal reflection to form a first blurred image light and a second blurred image light, and efficiently couples out the first blurred image light and projects it to the user side, and efficiently couples out the second blurred image light and projects it to the world side. The grating waveguide 100 provided in this embodiment allows external first image light 101 to enter the first waveguide substrate 20 via the coupling element 10, forming a second image light 102 (i.e., leaked 0th-order diffracted light) and a third image light 103. The second image light 102 propagates through the first waveguide substrate 20 to the scattering element 40, where it is scattered to form a blurred image light 104, which then propagates through the second waveguide substrate 50 to the second coupling element 60 and exits to the world side. The third image light 103 propagates through the first waveguide substrate 20 to the first coupling element 30. The fourth image light 105 is formed by diffraction through the first coupling element 30 and emitted to the user side; the world light 107 on the world side passes through the second waveguide substrate 50 and the first waveguide substrate 20 in sequence and is emitted to the user side; thus, the blurred image light 104 can be superimposed with a part of the image light (i.e., the fifth image light 106) and emitted to the world side, reducing the clarity of the fifth image light 106 to prevent the leakage of user privacy; since the world light 107 and another part of the image light (i.e., the fourth image light 104) can be emitted to the user's eyes on the user side, it can be applied to augmented reality devices.

[0061] In applications, the orthographic projection area of ​​the second coupling element 60 on the first waveguide substrate 20 can be located between the coupling element 10 and the first coupling element 30, or the first coupling element 30 can be located at the end away from the coupling element 10 to avoid affecting the world light 107 entering the user side. By providing multiple setting positions for the second coupling element 60, the fabrication process of the grating waveguide 100 is made more flexible.

[0062] like Figures 1-4 As shown, in one embodiment, the orthographic projection area of ​​the second coupling element 60 on the first waveguide substrate 20 is located between the coupling element 10 and the first coupling element 30. While satisfying the condition that the orthographic projection area of ​​the second coupling element 60 on the first waveguide substrate 20 is offset from the first coupling element 30, so as to avoid affecting the world light 107 entering the user side, the structural compactness of the grating waveguide 100 is improved.

[0063] like Figure 2 and Figure 4As shown, in one embodiment, the second coupling element 60 is a sawtooth groove region formed in the second waveguide substrate 50.

[0064] In applications, a sawtooth groove region can be directly formed in the second waveguide substrate 50 as the second coupling element 60, making the second coupling element 60 and the second waveguide substrate 50 an integrated structure. This facilitates assembly with other optical components and effectively improves optical path stability. The blurred image light 104 undergoes total internal reflection within the second waveguide substrate 50 and propagates to the sawtooth inclined surface of the second coupling element 60. Since the sawtooth inclined surface is tilted relative to the surface of the second waveguide substrate 50 near the world side, the blurred image light 104 no longer undergoes total internal reflection when it propagates to the sawtooth inclined surface of the second coupling element 60, but is refracted from the second waveguide substrate 50 to the world side.

[0065] like Figure 3 and Figure 4 As shown, in one embodiment, the grating waveguide 100 further includes a second light-transmitting cover 70 disposed on the user side.

[0066] In the application, a second light-transmitting cover 70 can be provided on the user side to protect the coupling element 10, the first waveguide substrate 20, and the first coupling element 30. The second light-transmitting cover 70 can be a glass substrate layer, plastic substrate layer, crystalline material substrate layer, or composite material substrate layer made of transparent materials such as glass (e.g., quartz glass, BK7 glass, etc.), plastic (e.g., polymethyl methacrylate, polycarbonate, etc.), crystalline material (e.g., sapphire (Al2O3), composite material (e.g., doped or modified glass).

[0067] like Figure 5 As shown, this application embodiment also provides an augmented reality device 1000, including an optical engine 200 and a grating waveguide 100 in any of the foregoing embodiments, wherein a first image light 101 is emitted by the optical engine 200 to the coupling element 10.

[0068] This application embodiment implements an augmented reality device 1000 based on a grating waveguide 100. By superimposing a blurred image light 104 with a fifth image light 106 and projecting it to the world side, the clarity of the fifth image light 106 is reduced, which can prevent the leakage of user privacy.

[0069] like Figure 7 As shown, this application embodiment also provides a virtual reality device 2000, including an optical engine 200, a light-shielding element 300 and a grating waveguide 100. The first image light 101 is emitted by the optical engine 200 to the coupling element 10. The light-shielding element 300 is disposed in the orthographic projection area of ​​the first coupling element 30 on the second waveguide substrate 50 and is used to block the fifth image light 106 and the world light 107.

[0070] This embodiment of the application adds a light-shielding element 300 to the grating waveguide 100. Since the light-shielding element 300 can block the world light 107 from entering the grating waveguide 100, only the fourth image light 105 is emitted to the user's eyes on the user side, thereby realizing the virtual reality device 2000. At the same time, since the light-shielding element 300 can block the fifth image light 106 from being emitted to the world side, only the blurred image light 104 is emitted to the world side, which can effectively prevent the leakage of user privacy.

[0071] In application, the side of the light-shielding element 300 facing the first coupling element 30 and the side away from the first coupling element 30 can both be light-absorbing film or reflective film. The light-absorbing film is used to absorb the fifth image light 106 or world light 107 incident on its surface, and the reflective film is used to reflect the fifth image light or world light 107 incident on its surface, so that the world light 107 cannot be incident on the user side and the fifth image light 106 cannot be emitted to the world side, thereby achieving the blocking of world light 107 and fifth image light 106.

[0072] like Figure 7 As shown, this application embodiment also provides a mixed reality device 3000, including an optical engine 200, a variable aperture 400 and a grating waveguide 100. The first image light 101 is emitted by the optical engine 200 to the coupling element 10. The variable aperture 400 is disposed in the orthographic projection area of ​​the first coupling element 30 on the second waveguide substrate 50 and is used to adjust the light transmission of the fifth image light 106 and the world light 107.

[0073] In applications, the variable aperture 400 is usually composed of multiple blades, and the size of the aperture can be changed by adjusting the position of the blades, adjusting the light transmission between 0% and 100%.

[0074] This embodiment adds a variable aperture 400 to the grating waveguide 100. Since the variable aperture 400 can adjust the amount of light emitted to the world side by the fifth image light 106 and the world light 107 entering the grating waveguide 100, it can realize augmented reality function when the amount of light is greater than 0 and virtual reality function when the amount of light is equal to 0, thereby realizing mixed reality function. When the amount of light is greater than 0, the display effect of augmented reality function can also be adjusted by adjusting the amount of light.

[0075] In applications, the optical engine 200 may include, but is not limited to, an image generator (e.g., a microdisplay based on display technologies such as Liquid Crystal on Silicon (LOCS), Organic Electroluminescence Display (OLED), Micro-LED, Mini-LED, etc.) for providing the first image light 101, a projection system (e.g., a lens, a mirror, a prism, etc.) for processing (e.g., collimating) and transmitting light signals, a mechanical structure for supporting and fixing optical elements, a drive device for controlling the movement of optical elements (e.g., a variable aperture 400), and a control system for monitoring and adjusting the operating state of the optical engine 200, etc.

[0076] In applications, augmented reality devices, virtual reality devices, and mixed reality devices can be configured as any wearable device (e.g., smart helmets, smart glasses) as needed, or they can be in other forms, such as head-up displays (HUDs).

[0077] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions 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 this application, and should all be included within the protection scope of this application.

Claims

1. A grating waveguide, characterized in that, It includes a first coupling element, a second coupling element, and a coupling element, a first waveguide substrate, a scattering element, and a second waveguide substrate stacked sequentially. The first waveguide substrate is located on the user side, and the second waveguide substrate is located on the world side. The coupling element and the first coupling element are spaced apart on the first waveguide substrate, and the second coupling element is located on the second waveguide substrate, with the orthographic projection area of ​​the second coupling element on the first waveguide substrate offset from the first coupling element. The first image light enters the first waveguide substrate through the coupling element, forming the second image light and the third image light; The second image light propagates through the first waveguide substrate to the scattering element, and is scattered by the scattering element to form blurred image light; The blurred image light propagates through the second waveguide substrate to the second coupling element, and is emitted to the world side through the second coupling element; The third image light propagates through the first waveguide substrate to the first coupling element, and is diffracted by the first coupling element to form a fourth image light and a fifth image light. The fourth image light is emitted to the user side, and the fifth image light is emitted to the world side. The world light from the world side passes through the second waveguide substrate and the first waveguide substrate in sequence and is emitted to the user side.

2. The grating waveguide as described in claim 1, characterized in that, The scattering element includes at least one of the following: a diffuser, a scattering film, a microlens array, frosted glass, a semi-transparent material layer, and a natural scattering material layer.

3. The grating waveguide as described in claim 1, characterized in that, The second coupling element is a sawtooth-shaped groove region formed in the second waveguide substrate.

4. The grating waveguide as described in claim 1, characterized in that, The second waveguide substrate is the first light-transmitting cover plate.

5. The grating waveguide as described in claim 1, 3, or 4, characterized in that, The orthographic projection region of the second coupling element on the first waveguide substrate is located between the coupling element and the first coupling element.

6. The grating waveguide according to any one of claims 1 to 4, characterized in that, It also includes a second light-transmitting cover plate located on the user side.

7. The grating waveguide according to any one of claims 1 to 4, characterized in that, The coupling element and the first coupling element are disposed on the surface of the first waveguide substrate near the user side.

8. An augmented reality device, characterized in that, Includes an optomechanism and a grating waveguide as described in any one of claims 1 to 7, wherein the first image light is emitted by the optomechanism to the coupling element.

9. A virtual reality device, characterized in that, The device includes an optical engine, a light-shielding element, and a grating waveguide as described in any one of claims 1 to 7. The first image light is emitted by the optical engine to the coupling element, and the light-shielding element is disposed in the orthogonal projection area of ​​the first coupling element on the second waveguide substrate to block the fifth image light and the world light.

10. A mixed reality device, characterized in that, The device includes an optomechanical system, a variable aperture, and a grating waveguide as described in any one of claims 1 to 7. The first image light is emitted by the optomechanical system to the coupling element, and the variable aperture is disposed in the orthogonal projection area of ​​the first coupling element on the second waveguide substrate to adjust the light transmittance of the fifth image light and the world light.

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