Grating assembly, optical waveguide assembly and augmented reality display device

Abstract

The present disclosure provides a grating assembly, an optical waveguide assembly and an augmented reality display device. The grating assembly comprises a coupling-in grating and a coupling-out grating which are located on the same surface of a base material and are spaced apart from each other, and the duty ratio of the coupling-out grating is gradually decreased in a direction away from the coupling-in grating. Therefore, in the direction away from the coupling-in grating, along with the gradual decrease of the duty ratio, the coupling-out of the coupling-out grating to light is gradually enhanced, the light can be prevented from being coupled out too early in an area close to the coupling-in grating, and the coupling-out grating has a relatively small duty ratio at an area away from the coupling-in grating, and thus has relatively high coupling-out efficiency. Thus, the arrangement mode of the coupling-out grating can improve the uniformity of the optical coupling-out efficiency of the coupling-out grating in different areas, so that the uniformity of display color is improved.

Description

Grating component, optical waveguide component and augmented reality display device

[0001] This application claims priority to the Chinese invention patent application entitled “Grating assembly, optical waveguide assembly and augmented reality display device” and application number 202311385535.0 filed on October 24, 2023, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present disclosure relates to the field of grating technology, and in particular, to a grating component, an optical waveguide component and an augmented reality display device. Background Art

[0003] Optical waveguides are a key technology for AR displays. Their basic principle is that the light emitted by an optical machine is coupled into the optical waveguide through a grating. As the light propagates through the waveguide, total internal reflection ensures that the light energy is not lost until it is coupled out through the grating at the position of the human eye. At the same time, because the position of the human eye varies from person to person and from time to time, we need to perform eye pupil expansion (EPE) on the light beam. By allowing these rays to reflect multiple times on the grating surface and couple out multiple times, the human eye can receive the light emitted by the optical machine within a certain range (Eye box, EB). However, the intensity distribution of the light coupled out by the current grating structure is extremely uneven, which seriously affects the user's visual experience.

[0004] Summary of the Invention

[0005] In one aspect of the present disclosure, the present disclosure provides a grating assembly. The grating assembly includes an in-coupling grating and an out-coupling grating located on the same surface of a substrate and spaced apart. According to an embodiment of the present disclosure, the duty cycle of the out-coupling grating gradually decreases in the direction away from the in-coupling grating. Thus, in the direction away from the in-coupling grating, as the duty cycle gradually decreases, the out-coupling of light by the out-coupling grating gradually increases, which can avoid premature out-coupling of light in the area close to the in-coupling grating. The out-coupling grating has a relatively small duty cycle in the area away from the in-coupling grating, and thus has a relatively large out-coupling efficiency. Therefore, the above-mentioned setting method of the out-coupling grating can improve the uniformity of the light out-coupling efficiency of the out-coupling grating in different areas, thereby improving the uniformity of the displayed color.

[0006] According to an embodiment of the present disclosure, the short-axis width of the out-coupling grating gradually increases in a direction away from the in-coupling grating.

[0007] According to an embodiment of the present disclosure, the major axis length of the out-coupling grating gradually decreases in a direction away from the in-coupling grating.

[0008] According to an embodiment of the present disclosure, in a direction away from the coupling-in grating, at least one of the duty cycle, the short-axis width, and the long-axis length of the coupling-out grating changes continuously.

[0009] According to an embodiment of the present disclosure, the grating assembly satisfies at least one of the following conditions: in the direction away from the coupling-in grating, the duty cycle of the coupling-out grating gradually decreases from A to B, wherein A is 0.75 to 0.95 and B is 0.3 to 0.7; in the direction away from the coupling-in grating, the short-axis width of the coupling-out grating gradually increases from C to D, wherein C is 20 nm to 80 nm and D is 120 nm to 200 nm; in the direction away from the coupling-in grating, the long-axis length of the coupling-out grating gradually decreases from E to F, wherein E is 300 nm to 400 nm and F is 250 nm to 300 nm.

[0010] According to an embodiment of the present disclosure, the tooth depth of the outcoupling grating gradually increases in a direction away from the incoupling grating.

[0011] According to an embodiment of the present disclosure, in a direction away from the coupling-in grating, the coupling-out grating includes a plurality of coupling-out regions, and the tooth depths of the plurality of coupling-out regions gradually increase, and the tooth depths of the same coupling-out region are the same.

[0012] According to an embodiment of the present disclosure, in a direction away from the coupling-in grating, the tooth depth of the coupling-out grating gradually increases from G to H, wherein G is 20 nm to 100 nm, and H is 120 nm to 200 nm.

[0013] In another aspect of the present disclosure, a light waveguide assembly is provided. According to an embodiment of the present disclosure, the light waveguide assembly comprises: a light waveguide; and the aforementioned grating assembly, disposed on one side of the light waveguide. As a result, the light intensity distribution of the light coupled out of the light waveguide is relatively uniform, helping to improve the uniformity of displayed colors. Those skilled in the art will appreciate that this light waveguide possesses all the features and advantages of the aforementioned grating assembly, and further details will not be provided here.

[0014] In another aspect of the present disclosure, an augmented reality display device is provided. According to an embodiment of the present disclosure, the augmented reality display device includes the aforementioned optical waveguide. As a result, the augmented reality display device displays better colors, contributing to a high-performance augmented reality display device. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and / or additional aspects and advantages of the present disclosure will become apparent and readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0016] FIG1 is a schematic diagram of the arrangement of a grating assembly in one embodiment of the present disclosure;

[0017] FIG2 is a schematic plan view and a cross-sectional view of the outcoupling grating in FIG1 ;

[0018] FIG3 is a graph showing the variation of the coupling efficiency of the outcoupling grating for red light R, green light G and blue light B as the width of the short axis of the outcoupling grating changes;

[0019] FIG4 is a graph showing the variation of the coupling efficiency of the outcoupling grating for red light R, green light G and blue light B with the tooth depth of the outcoupling grating;

[0020] FIG5 is a schematic diagram showing a gradual change in the duty cycle (CD) of an outcoupling grating in another embodiment of the present disclosure;

[0021] FIG6 is a schematic diagram of a gradual change in the short-axis width of an outcoupling grating in another embodiment of the present disclosure;

[0022] FIG7 is a schematic diagram of a gradual change in the major axis length of an outcoupling grating in another embodiment of the present disclosure;

[0023] FIG8 is a schematic diagram of the light intensity distribution of the out-coupling grating in another embodiment of the present disclosure and a schematic diagram of the light intensity distribution of the out-coupling grating in a comparative example;

[0024] FIG9 is a schematic diagram of a tooth depth gradient of a first one-dimensional outcoupling grating in another embodiment of the present disclosure;

[0025] FIG10 is a schematic diagram of a tooth depth gradient of a second one-dimensional outcoupling grating in another embodiment of the present disclosure;

[0026] FIG11 is a schematic diagram of a tooth depth gradient of a two-dimensional outcoupling grating in another embodiment of the present disclosure; and

[0027] FIG12 is a schematic structural diagram of an optical waveguide assembly in yet another embodiment of the present disclosure. DETAILED DESCRIPTION

[0028] The scheme of the present disclosure will be explained below with reference to the examples. Those skilled in the art will understand that the following examples are only used to illustrate the present disclosure and should not be considered to limit the scope of the present disclosure. If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the art or in accordance with the product instructions shall be followed.

[0029] The present disclosure is described below with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present disclosure in any way.

[0030] Current grating designs generally use a uniform grating structure, that is, at least one of the grating's period, duty cycle, tooth depth and other parameters remains consistent. However, a uniform grating structure means that the light beam outcoupling efficiency is the same at different positions on the grating. In the case of an outcoupling grating in an optical waveguide, if the grating's outcoupling efficiency is high, most of the light will be coupled out prematurely in the first few reflections, resulting in an extremely uneven distribution of the outcoupling light intensity. The light energy in the part close to the incoupling grating is extremely strong, while the light energy in the part far from the incoupling grating is extremely weak. This phenomenon is particularly evident for blue light due to the smaller diffraction angle and the greater number of diffractions of blue light. If the grating's outcoupling efficiency is low, the light energy cannot be fully utilized, resulting in a lower final light efficiency. This phenomenon has a greater impact on red light due to the larger diffraction angle of red light and the fewer interactions with the grating. In response to the above-mentioned technical problem of uneven light outcoupling, the inventors have discovered through a series of studies that the light outcoupling efficiency in different areas can be adjusted by changing the duty cycle of the outcoupling grating, thereby improving the uniformity of the light outcoupling of the outcoupling grating.

[0031] In view of this, in one aspect of the present disclosure, the present disclosure provides a grating assembly, which includes an in-coupling grating and an out-coupling grating located on the same surface of a substrate and spaced apart. According to an embodiment of the present disclosure, the duty cycle (CD) of the out-coupling grating gradually decreases in the direction away from the in-coupling grating. Thus, in the direction away from the in-coupling grating, as the duty cycle gradually decreases, the out-coupling of light by the out-coupling grating gradually increases, which can avoid premature out-coupling of light in the area close to the in-coupling grating. The out-coupling grating has a relatively small duty cycle in the area away from the in-coupling grating, and thus has a relatively large out-coupling efficiency. Therefore, the above-mentioned setting method of the out-coupling grating can improve the uniformity of the light out-coupling efficiency of the out-coupling grating in different areas, thereby improving the uniformity of the displayed color. Moreover, the above-mentioned outcoupling grating disclosed in the present invention not only reduces the diffraction efficiency of blue light in the area close to the incoupling grating, but also improves the diffraction efficiency of blue light in the area far away from the incoupling grating, so as to achieve an improvement in the uniformity of blue light outcoupling, and can also take into account the improvement of the uniformity of the diffraction efficiency of red and green light, thereby effectively improving the problem of color uniformity.

[0032] The grating assembly includes an in-coupling grating and an out-coupling grating located on the same surface of a substrate and spaced apart from each other. Specifically, the in-coupling grating and the out-coupling grating are located on the same surface of the same substrate. The specific type of substrate can be flexibly selected by those skilled in the art based on the specific application of the grating assembly. For example, in some virtual equipment, the in-coupling grating and the out-coupling grating are located on the same surface of an optical waveguide.

[0033] In some embodiments of the present disclosure, the arrangement and structural diagrams of the grating assembly can be seen with reference to Figures 1 and 2 . The incoupling grating 10 is disposed on one side of the outcoupling grating. The outcoupling grating can include three components: a first one-dimensional outcoupling grating 21, a second one-dimensional outcoupling grating 22, and a two-dimensional outcoupling grating 23 positioned between the first and second one-dimensional outcoupling gratings 21 and 22. The grooves of the two-dimensional outcoupling grating 23 are arranged in a rectangular array. Simulation tests were conducted on the outcoupling efficiency of different colors of light (including red light R, green light G, and blue light B), adjusting the duty cycle, groove tooth depth, and minor axis size of the outcoupling grating. The test results can be seen in Figures 3 and 4 . It can be seen that the light effects of blue light B, red light R and green light G are all positively correlated with the short-axis width of the out-coupling grating (the longer the short-axis width, the smaller the duty cycle) and the tooth depth. The rate of change of the out-coupling light effect of light of different colors relative to the short-axis width and the grating tooth depth is not the same. The diffraction efficiency of blue light (or the out-coupling light effect of blue light) changes very obviously with the short-axis width, while that of red light is relatively flat. When the short-axis width is larger (the smaller the duty cycle of the grating), the out-coupling efficiency of blue light is greater; when the tooth depth becomes deeper, the change in the out-coupling efficiency of red light is more significant relative to that of blue light. Based on the above research theory, in addition to improving the uniformity of the out-coupling light intensity of the grating by adjusting the duty cycle of the out-coupling grating, the present disclosure can also further improve the uniformity of the out-coupling light intensity of the out-coupling grating by adjusting parameters such as the short-axis width and tooth depth of the out-coupling grating. The specific improvement scheme is described in detail below. Those skilled in the art will understand that Figures 1 and 2 merely express one type of out-coupling grating structure, and the technical solution disclosed herein can also be used for out-coupling gratings of other structures, that is, Figures 1 and 2 are not limitations on the out-coupling grating structure in this application.

[0034] According to an embodiment of the present disclosure, referring to FIG5 , the duty cycle (CD) of the outcoupling grating (FIG. 5 shows the change in the duty cycle of the first one-dimensional outcoupling grating 21 and the second one-dimensional outcoupling grating 22 in FIG1 ) gradually decreases in a direction away from the incoupling grating (the incoupling grating is not shown in the figure; its positional relationship with the outcoupling grating can be seen in FIG1 ). As the duty cycle of the outcoupling grating changes, the diffraction efficiency of each color of light is reduced in areas close to the incoupling grating, while the diffraction efficiency of each color of light is increased in areas away from the incoupling grating, thereby improving the uniformity of the outcoupling of each color of light, especially the uniformity of the outcoupling of blue light, thereby effectively improving the problem of color uniformity. In some embodiments, as shown in FIG5 , in the direction away from the coupling-in grating, the duty cycle of the coupling-out grating gradually decreases from A(max) to B(min), where A is 0.75 to 0.95 (for example, A is 0.75, 0.78, 0.8, 0.85, 0.9, and 0.95), and B is 0.3 to 0.7 (for example, B is 0.3, 0.4, 0.5, 0.06, and 0.7). The coupling-out grating within the above range not only has good overall coupling-out efficiency, but also can improve the uniformity of the coupling-out efficiency of different colors of light at different positions. At the same time, in terms of process, the coupling-out grating with the above-mentioned duty cycle variation is easy to manufacture.

[0035] According to an embodiment of the present disclosure, referring to FIG6 , in a direction away from the coupling-in grating (the coupling-in grating is not shown in the figure, and its positional relationship with the coupling-out grating can be referred to FIG1 ), the short-axis width of the coupling-out grating (the change in the short-axis width of the two-dimensional coupling-out grating 23 in FIG1 is shown in FIG6 ) gradually increases, that is, the duty cycle gradually decreases. As the short-axis width of the coupling-out grating gradually increases, the diffraction efficiency of each color of light is reduced in the area close to the coupling-in grating, while the diffraction efficiency of each color of light is increased in the area away from the coupling-in grating, so as to achieve an improvement in the uniformity of the optical coupling-out of each color of light, especially the improvement in the uniformity of the blue light coupling-out, thereby effectively improving the problem of color uniformity. In some embodiments, in a direction away from the coupling-in grating, the short-axis width of the coupling-out grating gradually increases from C(min) to D(max). Among them, C is 20nm~80nm (for example, C is 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm), and D is 120nm~200nm (for example, D is 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, 200nm). The outcoupling grating within the above range not only has good outcoupling efficiency as a whole, but also can improve the uniformity of the outcoupling efficiency of different colors of light at different positions. At the same time, in terms of process, the outcoupling grating with varying short-axis width is easy to manufacture.

[0036] According to an embodiment of the present disclosure, referring to FIG7 , in a direction away from the coupling-in grating (the coupling-in grating is not shown in the figure, and its positional relationship with the coupling-out grating can be referred to FIG1 ), the major axis length of the coupling-out grating (the change in the major axis length of the two-dimensional coupling-out grating 23 in FIG1 is shown in FIG7 ) gradually decreases. As the major axis length of the coupling-out grating gradually decreases, the diffraction efficiency of each color of light is reduced in the area close to the coupling-in grating, while the diffraction efficiency of each color of light is increased in the area far from the coupling-in grating, so as to achieve an improvement in the uniformity of the optical coupling-out of each color of light, especially the improvement in the uniformity of the blue light coupling-out, thereby effectively improving the problem of color uniformity. In some embodiments, in a direction close to the coupling-in grating, the major axis length of the coupling-out grating gradually decreases from E to F. Among them, E is 300nm~400nm (for example, E is 300nm, 310nm, 320nm, 330nm, 340nm, 350nm, 360nm, 370nm, 380nm, 390nm, 400nm), and F is 250nm~300nm (for example, F is 250nm, 260nm, 270nm, 280nm, 290nm, 300nm). The outcoupling grating within the above range not only has good outcoupling efficiency as a whole, but also can improve the uniformity of the outcoupling efficiency of different colors of light at different positions. At the same time, in terms of process, the outcoupling grating with varying major axis length is easy to manufacture.

[0037] According to embodiments of the present disclosure, as shown in Figures 5 to 7, at least one of the duty cycle, minor axis width, and major axis length of the outcoupling grating varies continuously in a direction away from the incoupling grating. This continuous variation allows the duty cycle, minor axis width, and major axis length of the outcoupling grating to be adjusted at any different position, thereby more flexibly adjusting the light outcoupling efficiency of the outcoupling grating at different positions for different colors of light, thereby better improving the uniformity of the light outcoupling intensity and the uniformity of the displayed color. It should be noted that in actual production, it is difficult to achieve an ideal continuous variation in a straight line or curve in terms of process. Therefore, the "continuous variation" mentioned above in the present disclosure refers to the duty cycle, minor axis width, and major axis length of the outcoupling grating varying in a direction away from the incoupling grating, which continuously decreases or increases within a variation range, and the difference between two adjacent variation values ​​is small, for example, it can be controlled within a range of 5 nanometers (e.g., a difference of 5nm, 4nm, 3nm, 2nm, 1nm, etc.), rather than remaining unchanged within a larger range. For example, taking the change of the short axis width of the out-coupling grating as an example, the change range of the short axis width of the out-coupling grating is 60nm~140nm. In the direction away from the in-coupling grating, the short axis width of the out-coupling grating can be 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, 100nm, 105nm, 110nm, 115nm, 120nm, 125nm, 130nm, 135nm, 140nm, or the short axis width of the out-coupling grating can be 60nm, 61nm, 62nm, 63nm, 64nm, 65nm, 66nm, 67nm, 68nm, …, 131nm, 132nm, 133nm, 134nm, 135nm, 136nm, 137nm, 138nm, 139nm, 140nm.

[0038] In some specific embodiments, the tooth depth of the outcoupling grating is maintained at 90nm, and the changes in its duty cycle, minor axis width, and major axis length are shown in Figures 5 to 7. A schematic diagram of the light intensity coupled out of the outcoupling grating in the eye box at a certain angle is shown in Figure 8 (a). In a comparative example, the tooth depth of the outcoupling grating is 90nm, and the duty cycle, minor axis width, and major axis length are maintained unchanged. A schematic diagram of the light intensity coupled out of the outcoupling grating in the eye box at a certain angle is shown in Figure 8 (b). As can be seen from Figure 8, the light intensity distribution coupled out of the improved outcoupling grating of the present disclosure is relatively uniform, improving the uniformity of the optical waveguide display, while the light intensity distribution in the comparative example is extremely uneven.

[0039] According to an embodiment of the present disclosure, referring to Figures 9, 10, and 11, in a direction away from the coupling-in grating (the coupling-in grating is not shown in the figures, and its positional relationship with the coupling-out grating can be seen in Figure 1), the tooth depth (Depth) of the coupling-out grating (Figures 9, 10, and 11 respectively show the first one-dimensional coupling-out grating 21, the second one-dimensional coupling-out grating 22, and the two-dimensional coupling-out grating 23) gradually increases. As the tooth depth of the coupling-out grating gradually increases along the major axis length, the diffraction efficiency of each color of light is reduced in the area close to the coupling-in grating, while the diffraction efficiency of each color of light is increased in the area far from the coupling-in grating, so as to achieve an improvement in the uniformity of the optical coupling-out of each color of light, thereby effectively improving the problem of color uniformity.

[0040] In some embodiments of the present disclosure, the tooth depth of the outcoupling grating increases in a step-like manner in the direction away from the coupling-in grating, or in other words, the outcoupling grating is divided into multiple different regions in the direction away from the coupling-in grating, and the tooth depth of the multiple different regions gradually increases, but the tooth depth of the outcoupling grating portion in each region is the same. In some specific embodiments, as shown in Figures 9, 10, and 11, in the direction away from the coupling-in grating, the outcoupling grating includes multiple outcoupling regions S (Figures 9, 10, and 11 are each based on the example of three outcoupling regions S), and the tooth depth of the multiple outcoupling regions S gradually increases, and the tooth depth of the same outcoupling region is the same. This not only facilitates the process of manufacturing, but also effectively improves the uniformity of the outcoupling light intensity of the outcoupling grating. Of course, those skilled in the art will understand that in the direction close to the coupling-in grating, the outcoupling grating includes more outcoupling regions S, such as 4 outcoupling regions S, 5 outcoupling regions S, 6 outcoupling regions S, or 8 outcoupling regions S.

[0041] In some embodiments of the present disclosure, in the direction away from the coupling-in grating, the tooth depth of the coupling-out grating gradually increases from G to H, where G is 20nm to 100nm (for example, G is 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm), and H is 120nm to 200nm (for example, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, 200nm). The coupling-out grating within the above range not only has good overall coupling-out efficiency, but also can improve the uniformity of the coupling-out efficiency of different colors of light at different positions. At the same time, in terms of process, the coupling-out grating with the above-mentioned tooth depth variation is easy to manufacture.

[0042] In another aspect of the present disclosure, a light waveguide assembly is provided. According to an embodiment of the present disclosure, referring to FIG12 , the light waveguide assembly includes: a light waveguide 100; and the aforementioned grating assembly, namely, the grating assembly includes the aforementioned in-coupling grating 10 and out-coupling grating 20, with the grating assembly 200 disposed on one side of the light waveguide 100. As a result, the light intensity distribution of the light coupled out of the light waveguide is relatively uniform, helping to improve the uniformity of displayed colors. Those skilled in the art will appreciate that this light waveguide possesses all the features and advantages of the grating assembly described above, and further details will not be provided here.

[0043] In another aspect of the present disclosure, an augmented reality display device is provided. According to an embodiment of the present disclosure, the augmented reality display device includes the aforementioned optical waveguide assembly. As a result, the augmented reality display device exhibits superior color, contributing to the realization of a high-performance augmented reality display device. Those skilled in the art will appreciate that the augmented reality display device possesses many of the features and advantages of the aforementioned optical waveguide assembly, which will not be elaborated upon here.

[0044] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0045] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and features of different embodiments or examples, unless they are mutually inconsistent.

[0046] Although the embodiments of the present disclosure have been shown and described above, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present disclosure. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present disclosure.

Claims

1. A grating assembly, comprising an in-coupling grating and an out-coupling grating located on the same surface of a substrate and spaced apart from each other, wherein the duty cycle of the out-coupling grating gradually decreases in a direction away from the in-coupling grating. 2 . The grating assembly according to claim 1 , wherein the short axis width of the out-coupling grating gradually increases in a direction away from the in-coupling grating. 3 . The grating assembly according to claim 1 , wherein the major axis length of the out-coupling grating gradually decreases in a direction away from the in-coupling grating.

4. The grating assembly according to any one of claims 1 to 3, wherein in a direction away from the coupling-in grating, at least one of the duty cycle, the short-axis width and the long-axis length of the coupling-out grating changes continuously.

5. The grating assembly according to any one of claims 1 to 3, wherein at least one of the following conditions is satisfied: In the direction away from the coupling-in grating, the duty cycle of the coupling-out grating gradually decreases from A to B, where: A is 0.75-0.95, B is 0.3-0.7; In a direction away from the coupling-in grating, the short axis width of the coupling-out grating gradually increases from C to D, wherein C is 20 nm to 80 nm, and D is 120 nm to 200 nm; In the direction away from the coupling-in grating, the major axis length of the coupling-out grating gradually decreases from E to F, wherein E is 300nm-400nm and F is 250nm-300nm.

6. The grating assembly according to any one of claims 1 to 3, wherein the tooth depth of the out-coupling grating gradually increases in a direction away from the in-coupling grating.

7. The grating assembly according to claim 6, wherein in the direction away from the coupling-in grating, the coupling-out grating comprises a plurality of coupling-out regions, and the tooth depths of the plurality of coupling-out regions gradually increase, and the tooth depths of the same coupling-out region are the same.

8. The grating assembly according to claim 6, wherein in a direction away from the coupling-in grating, the tooth depth of the coupling-out grating gradually increases from G to H, wherein: G is 20nm~100nm, and H is 120nm~200nm.

9. An optical waveguide component comprising: Optical waveguides; The grating component according to any one of claims 1 to 8, wherein the grating component is arranged on one side of the optical waveguide.

10. An augmented reality display device, comprising the optical waveguide assembly according to claim 9.

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