An optical waveguide assembly and near-eye display device
By introducing a combined structure of coupling grating, redirection grating and output grating into the optical waveguide assembly, the problem of uneven light output in optical waveguide technology is solved, and the brightness uniformity of the display screen is improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- APPOTRONICS CORP LTD
- Filing Date
- 2025-05-20
- Publication Date
- 2026-06-09
AI Technical Summary
Existing optical waveguide technology suffers from uneven light output, which negatively impacts the user's viewing experience.
The system employs a combination structure of an input grating, a redirection grating, and an output grating. The redirection grating deflects and expands the incident light, widening the light beam and dispersing it, thus preventing light concentration and improving the uniformity of the output brightness.
It improves the brightness uniformity of the displayed image, enhancing the user's visual experience.
Smart Images
Figure CN224341699U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of optical technology, and in particular to an optical waveguide assembly and a near-eye display device. Background Technology
[0002] Augmented Reality (AR), as a cutting-edge reality display technology, innovatively integrates the real environment with virtual images to bring users an immersive interactive experience. The core architecture of this technology includes two key components: a projector and an optical display screen. The optical display screen is responsible for accurately projecting the virtual content displayed on the miniature display inside the projector onto the user's eyes while maintaining light transmission, allowing users to clearly perceive the external real scene while receiving virtual information, thus achieving seamless integration and interaction between virtual and real scenes.
[0003] Currently, waveguide technology is the mainstream development direction in the field of optical displays, mainly divided into two major technical routes: geometric array waveguides and diffractive waveguides. In the diffractive waveguide technology system, surface relief grating waveguides stand out with significant advantages: they not only have a high degree of design flexibility, which can meet the needs of diverse product forms, but also can be adapted to mature industrial processes such as semiconductor manufacturing and precision testing. Therefore, they have become the preferred solution for global AR device manufacturers in R&D and mass production.
[0004] In the development of waveguide technology, display uniformity is one of the key indicators for evaluating its performance, directly affecting the user's visual experience. Current optical waveguide technology still suffers from significant uneven light emission, negatively impacting the user's viewing experience. Utility Model Content
[0005] The purpose of this application is to provide an optical waveguide component and a near-eye display device, aiming to provide a solution for improving the uniformity of emitted light brightness.
[0006] The embodiments of this application are implemented as follows: an optical waveguide component includes: a waveguide substrate, a coupling grating, a redirection grating, and an output grating;
[0007] The coupling-in grating, the redirection grating, and the coupling-out grating are disposed on the surface of the waveguide substrate, and the redirection grating is located between the coupling-in grating and the coupling-out grating along the optical path;
[0008] The coupling grating is used to couple incident light into the waveguide substrate;
[0009] The redirection grating is used to deflect and extend the propagation direction of at least a portion of the incident light rays from the waveguide substrate, and to diffract at least a portion of the incident light rays to obtain a first diffracted ray.
[0010] The coupling grating is used to couple the first diffracted light rays out of the waveguide substrate.
[0011] In one embodiment, the coupling grating is a one-dimensional grating, which is used to couple the incident light rays into the waveguide substrate along a first direction; the redirection grating is used to cause the incident light rays to extend in at least one direction inclined to the first direction.
[0012] In one embodiment, the redirection grating is a two-dimensional grating used to extend the incident light rays in at least two directions inclined to the first direction.
[0013] In one embodiment, the redirection grating includes a symmetrically distributed first sub-grating and a second sub-grating, both of which are one-dimensional gratings; the first sub-grating is used to deflect a portion of the incident light rays to a second direction inclined to the first direction for propagation and expansion, and the second sub-grating is used to cause another portion of the incident light rays to expand along a third direction inclined to the first direction.
[0014] In one embodiment, the redirection grating is used to cause the incident light to extend in a direction perpendicular to the first direction.
[0015] In one embodiment, the redirection grating is used to direct the first diffracted ray into the coupling grating along the first direction.
[0016] In one embodiment, the coupling grating is a two-dimensional grating used to diffract the incident light to obtain a second diffracted light along a first direction, and a third and a fourth diffracted light located on both sides of the second diffracted light; the redirection grating includes a third sub-grating and a fourth sub-grating symmetrically distributed and spaced apart with respect to the second diffracted light, both of which are one-dimensional gratings. The third sub-grating is used to cause the third diffracted light to expand and diffract along a fourth direction inclined to the first direction to obtain a portion of the first diffracted light, and the fourth sub-grating is used to cause the fourth diffracted light to expand and diffract along a fifth direction inclined to the first direction to obtain another portion of the first diffracted light; the second diffracted light enters the coupling grating through the space between the third and fourth sub-gratings.
[0017] In one embodiment, the fourth direction and the fifth direction are symmetrical about the first direction, and the propagation direction of the first diffracted ray is the same as the propagation direction of the second diffracted ray.
[0018] In one embodiment, the coupling grating is a two-dimensional grating, comprising a symmetrically distributed first sub-coupling grating and a second sub-coupling grating; the first sub-coupling grating is used to receive a portion of the first diffracted light and deflect a portion of the first diffracted light to the second sub-coupling grating, the second sub-coupling grating is used to diffract a portion of the first diffracted light from the waveguide substrate, the second sub-coupling grating is used to receive another portion of the first diffracted light and deflect another portion of the first diffracted light to the first sub-coupling grating, and the first sub-coupling grating is used to diffract another portion of the first diffracted light from the waveguide substrate.
[0019] Another objective of this application is to provide a near-eye display device, which includes an image source and an optical waveguide assembly as described in the above embodiments, the optical waveguide assembly being located on the light-emitting side of the image source.
[0020] The optical waveguide assembly and near-eye display device provided in this application have the following advantages:
[0021] The optical waveguide component provided in this application uses a redirection grating to deflect and expand the incident light, which can widen the incident light and disperse the incident light within its width to avoid light concentration. This makes the brightness of the first diffracted light uniform after it is coupled out of the coupling grating, thus improving the brightness uniformity of the image seen by the human eye. Attached Figure Description
[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments 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.
[0023] Figure 1 This is a schematic diagram of an existing waveguide architecture;
[0024] Figure 2 yes Figure 1 Simulation diagram of the light output distribution of the waveguide architecture shown;
[0025] Figure 3 This is a schematic diagram of another existing waveguide architecture;
[0026] Figure 4 yes Figure 3 Simulation diagram of the light output distribution of the waveguide architecture shown;
[0027] Figure 5 This is a schematic diagram of the structure of an optical waveguide component provided in one embodiment of this application;
[0028] Figure 6 This is a schematic diagram of the structure of an optical waveguide component provided in one embodiment of this application;
[0029] Figure 7 This is a schematic diagram of the structure of an optical waveguide component provided in one embodiment of this application;
[0030] Figure 8 This is a schematic diagram of the structure of an optical waveguide component provided in one embodiment of this application.
[0031] The markings in the diagram mean:
[0032] 014 - One-dimensional grating;
[0033] 100 - Optical waveguide assembly;
[0034] 1. 013 - Waveguide substrate, 10 - First surface, 11 - First region, 12 - Second region, 121 - Third sub-region, 122 - Fourth sub-region, 13 - Third region, 131 - First sub-region, 132 - Second sub-region;
[0035] 5. 011 - Coupled-in grating;
[0036] 6-Redirection grating, 61-First sub-grating, 62-Second sub-grating, 63-Third sub-grating, 64-Fourth sub-grating;
[0037] 7, 012 - Coupling grating, 71 - First sub-coupling grating, 72 - Second sub-coupling grating;
[0038] D1 - First direction, D2 - Second direction, D3 - Third direction, D4 - Fourth direction, D5 - Fifth direction. Detailed Implementation
[0039] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.
[0040] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly or indirectly fixed to or set on that other component. When a component is referred to as "connected to" another component, it can be directly or indirectly connected to that other component. The terms "upper," "lower," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the purpose of description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this patent. The terms "first" and "second" are used only for the purpose of description and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. "A plurality" means two or more, unless otherwise explicitly specified.
[0041] In the description of this application, unless otherwise stated, " / " indicates that the objects before and after are in an "or" relationship. For example, A / B can mean A or B. "And / or" in this application is merely a description of the relationship between the related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. A and B can be single or multiple. Furthermore, in the description of this application, "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, at least one of a, b, and c can represent: a, b, c, a+b, a+c, b+c, a+b+c, where a, b, and c can be single or multiple. As another example, at least one of a, b, or c can represent: a, b, c, a+b, a+c, b+c, a+b+c, where a, b, and c can be single or multiple.
[0042] To illustrate the technical solutions described in this application, the following detailed description is provided in conjunction with specific drawings and embodiments.
[0043] like Figure 1As shown, a common architecture for diffractive waveguides is a one-dimensional coupling grating paired with a two-dimensional coupling grating. This architecture allows for a larger third region and display area, better matching the waveguide's requirements for a large eyebox and wide field of view. Image light from the micro-projector is coupled into the waveguide substrate 013 by the coupling grating 011, and directly transmitted within the waveguide substrate 013 to the coupling grating 012 located in the third region via total internal reflection. The coupling grating 012 is a two-dimensional grating. Due to the diffraction characteristics of a two-dimensional grating, the light continues to propagate in six directions after passing through it. Some light is coupled out, while some continues to undergo pupil expansion and deflection within the waveguide substrate 013. Ultimately, image light is coupled out throughout the entire third region, achieving a larger eyebox and field of view. However, also due to the diffraction characteristics of the two-dimensional grating, the beam has high pupil expansion and deflection efficiency immediately upon entering the third region, resulting in high coupling efficiency at this point. Therefore, the human eye often sees a distinct "bright band" in the center of an image, precisely because there are more outgoing rays in the middle of the third region, such as... Figure 2 As shown.
[0044] like Figure 3 As shown, another existing waveguide architecture has a coupling grating on the waveguide substrate 013 composed of two symmetrical one-dimensional gratings 014. Light received by the coupling grating 011 passes through the waveguide substrate 013 and is directed to the two one-dimensional gratings 014. Light from one grating 014 then passes through the other grating 014 before exiting to form an image. The two gratings 014 act as pupil expanders and a third region for each other. This architecture requires light to pass through both gratings 014 sequentially before being coupled out and received by the human eye. Only half of the area in the central region allows light to be coupled out, resulting in a dark band in the center of the displayed image. Figure 4 As shown.
[0045] Current waveguide architectures show that uniformity needs improvement.
[0046] Next, please see Figures 5 to 8 As shown in the figure, this application embodiment provides an optical waveguide component 100 with high display uniformity.
[0047] See Figure 5 , Figure 6 , Figure 7 and Figure 8As shown, this application embodiment first provides an optical waveguide assembly 100, which includes a waveguide substrate 1, a coupling grating 5, a redirection grating 6, and an output grating 7. The coupling grating 5, the redirection grating 6, and the output grating 7 are all disposed on the surface of the waveguide substrate 1. The waveguide substrate 1 includes multiple regions, such as a first region 11, a second region 12, and a third region 13. The coupling grating 5 is disposed in the first region 11 and is used to couple incident light into the waveguide substrate 1. The redirection grating 6 is disposed in the second region 12 and is used to deflect and expand incident light from the waveguide substrate 1, and to diffract the light grating to obtain a first diffracted light. The output grating 7 is disposed in the third region 13 and is used to couple the first diffracted light out.
[0048] The redirection grating 6 is used to deflect and expand the propagation direction of at least a portion of the incident light rays from the waveguide substrate 1. In other words, after the incident light rays enter the redirection grating 6, the incident light rays propagate and expand in a manner that deflects at a certain angle relative to their coupling direction. At this time, the width of the expanded light rays increases, and the light rays are dispersed in the width direction, which can avoid the light rays from concentrating. Thus, the first diffracted light rays are relatively dispersed and have a certain width. After the first diffracted light rays are coupled out, a large display area and field of view are formed, and the brightness of the resulting display screen can be relatively uniform.
[0049] The optical waveguide component 100 provided in this application embodiment uses a redirection grating 6 to deflect and expand the incident light, which can widen the incident light and disperse the incident light within its width to avoid light concentration. As a result, the brightness of the first diffracted light after being coupled out from the coupling grating 7 is uniform, improving the brightness uniformity of the image seen by the human eye.
[0050] In one embodiment of this application, the coupling grating 5, the redirection grating 6, and the coupling grating 7 are disposed on the same surface of the waveguide substrate 1, for example, the first surface 10 of the waveguide substrate 1.
[0051] In this embodiment, the redirection grating 6 is located in the second region 12. In the optical path direction, the second region 12 is located between the first region 11 and the third region 13 of the waveguide substrate 1. Here, the relative positional relationship between the first region 11, the second region 12, and the third region 13 is determined based on the transmission relationship of light rays; there is no restriction on the order of up, down, left, and right on this optical waveguide assembly 100. In some embodiments, the shapes of the first region 11, the second region 12, and the third region 13 include, but are not limited to, circles, ellipses, near-circular shapes, triangles, rectangles, and other polygons.
[0052] In some embodiments, there may be no visible boundary between the first region 11, the second region 12 and the third region 13 of the waveguide substrate 1. This can be identified from the design features of the optical waveguide assembly 100: light needs to pass through the first region 11, the second region 12 and the third region 13 in sequence before it can be received by the human eye.
[0053] In one embodiment of this application, such as Figure 5 , Figure 6 As shown, the coupling grating 5 is a one-dimensional grating used to couple incident light into the waveguide substrate 1, so that the incident light undergoes total internal reflection within the waveguide substrate 1 at an incident angle greater than or equal to the critical angle. Specifically, as... Figure 5 , Figure 7 As shown, the coupling grating 5 is also used to couple the incident light beam into the second region 12 along the first direction D1, and to direct the incident light beam into the redirection grating 6. The light beam entering the waveguide substrate 1 through the coupling grating 5 first propagates to the second region 12, where the redirection grating 6 deflects the incident light beam to propagate and extend it in at least one direction inclined to the first direction D1. In this way, the width of the incident light beam can be increased.
[0054] In one embodiment of this application, such as Figure 5 , Figure 7 As shown, the redirection grating 6 is used to propagate and expand the incident light in a direction perpendicular to the first direction D1. After the incident light passes through the redirection grating 6, its propagation direction is perpendicular to the direction in which it enters the redirection grating 6, resulting in the maximum width of the light and better light uniformity.
[0055] In one embodiment of this application, such as Figure 5 As shown, the redirection grating 6 is a two-dimensional grating. The two-dimensional grating is used to deflect the incident light rays to propagate and expand in one or two directions inclined to the first direction D1.
[0056] like Figure 5 As shown, in one embodiment of this application, the redirection grating 6 is a two-dimensional grating. This two-dimensional grating is used to deflect the incident light rays to propagate and extend in a direction perpendicular to the first direction D1.
[0057] like Figure 6 and Figure 7 As shown, the redirection grating 6 includes a symmetrically distributed first sub-grating 61 and a second sub-grating 62, both of which are one-dimensional gratings. The first sub-grating 61 is used to extend a portion of the incident light along a second direction D2 inclined to the first direction D1, and the second sub-grating 62 is used to extend another portion of the incident light along a third direction D3 inclined to the first direction D1.
[0058] like Figure 6 and Figure 7 As shown, in one embodiment of this application, the second direction D2 is parallel to the third direction D3. In this case, the two are actually the positive and negative directions of the same direction. The first sub-grating 61 and the second sub-grating 62 respectively cause the light to expand in opposite directions in the same direction and obtain a certain beam width.
[0059] In other alternative embodiments, the second direction D2 and the third direction D3 may not be parallel.
[0060] like Figure 6 and Figure 7 As shown, in one embodiment of this application, the second region 12 includes multiple sub-regions, such as a third sub-region 121 and a fourth sub-region 122. The first sub-grating 61 of the redirection grating 6 is disposed in the third sub-region 121, and the fourth sub-grating 64 is disposed in the fourth sub-region 122.
[0061] like Figure 5 , Figure 6 and Figure 8 As shown, in one embodiment of this application, the coupling grating 7 includes a symmetrically distributed first sub-coupling grating 71 and a second sub-coupling grating 72. The first sub-coupling grating 71 is used to receive a first portion of the first diffracted light and deflect the first portion of the first diffracted light to the second sub-coupling grating 72. The second sub-coupling grating 72 diffracts the first portion of the first diffracted light and couples it out of the waveguide substrate 1. The second sub-coupling grating 72 is used to receive a second portion of the first diffracted light and deflect the first portion of the first diffracted light to the first sub-coupling grating 71. The first sub-coupling grating 71 diffracts the second portion of the first diffracted light and couples it out of the waveguide substrate 1.
[0062] In one embodiment of this application, such as Figure 5 , Figure 6 and Figure 7 As shown, the redirection grating 6 is used to direct the first diffracted ray into the coupling grating 7 along the first direction D1.
[0063] Thus, the direction in which light enters the redirection grating 6 is the same as the direction in which it exits the redirection grating 6.
[0064] like Figure 7 As shown, in one embodiment of this application, the coupling grating 7 is a two-dimensional grating, which is used to receive the first diffracted beam from the redirection grating 6, and to continue to diffract the first diffracted beam in multiple directions and couple it out of the waveguide substrate 1.
[0065] Specifically, such as Figure 5As shown, the coupling grating 5 is a one-dimensional grating. Light rays coupled into the waveguide substrate 1 via the coupling grating 5 propagate along the first direction D1 to the second region 12. In the second region 12, the redirection grating 6 deflects the light rays to propagate in a direction perpendicular to the first direction D1. After multiple diffractions in the second region 12, the light rays still propagate in a direction parallel to the first direction D1 to the third region 13, but the light width increases after several pupil expansions in a direction perpendicular to the light propagation. The coupling grating 7 is located in the third region 13 and includes a first sub-coupling grating 71 and a second sub-coupling grating 72. The corresponding third region 13 includes a first sub-region 131 and a second sub-region 132. The light rays reaching the first sub-region 131 are deflected by the first sub-coupled grating 71 and then to the second sub-region 132. After being diffracted by the second sub-coupled grating 72 in the second sub-region 132, the light rays reaching the second sub-region 132 are deflected by the second sub-coupled grating 72 and then to the first sub-region 131. After being diffracted by the first sub-coupled grating 71 in the first sub-region 131, the light rays are then emitted from the waveguide substrate 1.
[0066] like Figure 6 As shown, the coupling grating 5 is a one-dimensional grating. Light rays coupled into the waveguide substrate 1 via the coupling grating 5 are transmitted along the first direction D1 to the second region 12. In the second region 12, the redirection grating 6 deflects the light rays to a direction perpendicular to the direction of transmission along the first direction D1. The third sub-region 121 and the fourth sub-region 122 are symmetrical about the first direction D1, as are the third sub-grating 63 and the fourth sub-grating 64. After the incident light rays enter the second region 12, the first sub-grating 61 located in the third sub-region 121 refracts part of the light rays into the third sub-region 121 to expand the pupil, and then transmits the light rays along the first direction D1 to the third region 13; the fourth sub-grating 64 located in the fourth region refracts part of the light rays into the fourth sub-region 122 to expand the pupil, and then transmits the light rays along the first direction D1 to the third region 13.
[0067] Specifically, the first sub-grating 61 located in the third sub-region 121 refracts part of the light into the third sub-region 121 to expand the pupil, and then refracts the light again into the first direction D1, so that the light is transmitted along the first direction D1 to the first sub-region 131 of the third region 13. The light reaching the first sub-region 131 is deflected into the second sub-region 132 after being acted upon by the first sub-coupler grating 71. After being diffracted by the second sub-coupler grating 72 in the second sub-region 132, the light exits from the waveguide substrate 1. The fourth sub-grating 64 located in the fourth region refracts part of the light into the fourth sub-region 122 to expand the pupil, and then refracts the light again into the first direction D1, so that the light is transmitted to the second sub-region 132 of the third region 13. The light reaching the second sub-region 132 is deflected into the first sub-region 131 after being acted upon by the second sub-coupler grating 72. After being diffracted by the first sub-coupler grating 71 in the first sub-region 131, the light exits from the waveguide substrate 1.
[0068] like Figure 7 As shown, the coupling grating 5 is a one-dimensional grating. Light rays coupled into the waveguide substrate 1 via the coupling grating 5 are transmitted along the first direction D1 to the second region 12. In the second region 12, the redirection grating 6 deflects the light rays to propagate in a direction perpendicular to the first direction D1. The third sub-region 121 and the fourth sub-region 122 are symmetrical about the first direction D1, as are the third sub-grating 63 and the fourth sub-grating 64. After the incident light rays enter the second region 12, the first sub-grating 61, located in the third sub-region 121, refracts part of the light rays into the third sub-region 121 to expand the pupil, and then refracts the light rays again into the first direction D1, causing the light rays to propagate along the first direction D1 to the third region 13; the fourth sub-grating 64, located in the fourth region, refracts part of the light rays into the fourth sub-region 122 to expand the pupil, and then causes the light rays to propagate along the first direction D1 to the third region 13.
[0069] In the third region 13, the coupling grating 7 is a two-dimensional grating that diffracts the light rays incident from the third sub-grating 63 and the fourth sub-grating 64 into multiple directions and couples them out of the waveguide substrate 1.
[0070] In one embodiment of this application, such as Figure 8 As shown, the coupling grating 5 is a two-dimensional grating used to diffract the incident light to obtain a second, third, and fourth diffracted ray. The redirection grating 6 is a one-dimensional grating, comprising a third sub-grating 63 and a fourth sub-grating 64 that are symmetrically distributed and spaced apart with respect to the second diffracted ray. Both the third sub-grating 63 and the fourth sub-grating 64 are one-dimensional gratings. The third sub-grating 63 is used to extend and diffract the third diffracted ray along a fourth direction D4 inclined to the first direction D1 to obtain a portion of the first diffracted ray. The fourth sub-grating 64 is used to extend and diffract the fourth diffracted ray along a fifth direction D5 inclined to the first direction D1 to obtain another portion of the first diffracted ray. The second diffracted ray enters the coupling grating 7 through the space between the third sub-grating 63 and the fourth sub-grating 64.
[0071] In one embodiment of this application, such as Figure 8 As shown, the fourth direction D4 and the fifth direction D5 are symmetrical about the first direction D1, and the propagation direction of the first diffracted ray is the same as that of the second diffracted ray. The first diffracted ray and the second diffracted ray enter the coupling grating 7 at the same angle.
[0072] In an embodiment, such as Figure 8As shown, the coupling grating 7 may include a first sub-coupling grating 71 and a second sub-coupling grating 72 that are symmetrically distributed with respect to the second diffracted rays. The first sub-coupling grating 71 is used to receive a first portion of the first diffracted rays and the second diffracted rays and deflect the first portion of the first diffracted rays and the second diffracted rays to the second sub-coupling grating 72. The second sub-coupling grating 72 diffracts the first portion of the first diffracted rays and the second diffracted rays and couples them out from the waveguide substrate 1. The second sub-coupling grating 72 is used to receive a second portion of the first diffracted rays and the second diffracted rays and deflect the first portion of the first diffracted rays and the second diffracted rays to the first sub-coupling grating 71. The first sub-coupling grating 71 diffracts the second portion of the first diffracted rays and the second diffracted rays and couples them out from the waveguide substrate 1.
[0073] like Figure 8 As shown, the coupling grating 5, located in the first region 11, is a two-dimensional grating used to couple light into the waveguide substrate 1, allowing the light to propagate within the waveguide at an incident angle greater than or equal to the critical angle through total internal reflection. Due to the characteristics of the two-dimensional grating, light can propagate in the waveguide along six directions. Light rays of diffraction orders (-1, -1), (1, -1), and (0, -2) can reach the third region 13 and be coupled out of the waveguide substrate 1 to be received by the human eye. The (-1, -1) and (1, -1) order diffracted light coupled into the waveguide substrate 1 via the coupling grating 5 first enters the third sub-region 121 and the fourth sub-region 122 of the second region 12. The redirection grating 6 includes a third sub-grating 63 and a fourth sub-grating 64, both of which are one-dimensional gratings with different orientations. Figure 8 As shown, in the third sub-region 121, the (-1, -1) order diffracted light, after being diffracted by the third sub-grating 63, propagates in the same direction as the (0, -2) order diffracted light; in the fourth sub-region 122, the (1, -1) order diffracted light, after being diffracted by the fourth sub-grating 64, propagates in the same direction as the (0, -2) order diffracted light. Therefore, after passing through the redirection grating 6, the light propagates to the third region 13 in a direction parallel to the (0, -2) order coupled light, but the beam width increases in the direction perpendicular to the light propagation. The first sub-coupling grating 71 and the second sub-coupling grating 72 are two-dimensional gratings, located in the first sub-region 131 and the second sub-region 132 of the third region 13, respectively. The light rays reaching the first sub-region 131 are deflected to the second sub-region 132 after being acted upon by the first sub-coupled grating 71. After being diffracted by the second sub-coupled grating 72 in the second sub-region 132, they are emitted from the waveguide substrate 1. The light rays reaching the second sub-region 132 are deflected to the first sub-region 131 after being acted upon by the second sub-coupled grating 72. After being diffracted by the first sub-coupled grating 71 in the first sub-region 131, they are emitted from the waveguide substrate 1.
[0074] Finally, this application also provides a near-eye display device, which includes an image source and an optical waveguide assembly 100 as described in the above embodiments, the optical waveguide assembly 100 being located on the light-emitting side of the image source. Specifically, the coupling grating 5 corresponds to the light-emitting side of the image source and is used to couple the light emitted from the image source into the waveguide substrate 1.
[0075] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. An optical waveguide component, characterized in that, include: Waveguide substrate, coupling grating, redirection grating, and output grating; The coupling-in grating, the redirection grating, and the coupling-out grating are disposed on the surface of the waveguide substrate, and the redirection grating is located between the coupling-in grating and the coupling-out grating along the optical path; The coupling grating is used to couple incident light into the waveguide substrate; The redirection grating is used to deflect and extend the propagation direction of at least a portion of the incident light rays from the waveguide substrate, and to diffract at least a portion of the incident light rays to obtain a first diffracted ray. The coupling grating is used to couple the first diffracted light rays out of the waveguide substrate.
2. The optical waveguide assembly as described in claim 1, characterized in that, The coupling grating is a one-dimensional grating, which is used to couple the incident light into the waveguide substrate along a first direction; the redirection grating is used to extend the incident light in at least one direction inclined to the first direction.
3. The optical waveguide assembly as described in claim 2, characterized in that, The redirection grating is a two-dimensional grating used to extend the incident light rays in at least two directions inclined to the first direction.
4. The optical waveguide assembly as described in claim 2, characterized in that, The redirection grating includes a symmetrically distributed first sub-grating and a second sub-grating, both of which are one-dimensional gratings. The first sub-grating is used to deflect a portion of the incident light rays to a second direction inclined to the first direction for propagation and expansion, and the second sub-grating is used to cause another portion of the incident light rays to expand along a third direction inclined to the first direction.
5. The optical waveguide assembly as described in claim 2, characterized in that, The redirection grating is used to extend the incident light rays in a direction perpendicular to the first direction.
6. The optical waveguide assembly as described in claim 2, characterized in that, The redirection grating is used to direct the first diffracted ray into the coupling grating along the first direction.
7. The optical waveguide assembly as described in claim 1, characterized in that, The coupling grating is a two-dimensional grating used to diffract the incident light to obtain a second diffracted light along a first direction, and a third and fourth diffracted light located on both sides of the second diffracted light. The redirection grating includes a third sub-grating and a fourth sub-grating symmetrically distributed and spaced apart with respect to the second diffracted light. Both the third and fourth sub-gratings are one-dimensional gratings. The third sub-grating is used to cause the third diffracted light to expand and diffract along a fourth direction inclined to the first direction to obtain a portion of the first diffracted light. The fourth sub-grating is used to cause the fourth diffracted light to expand and diffract along a fifth direction inclined to the first direction to obtain another portion of the first diffracted light. The second diffracted light enters the coupling grating through the space between the third and fourth sub-gratings.
8. The optical waveguide assembly as described in claim 7, characterized in that, The fourth direction and the fifth direction are symmetrical about the first direction, and the propagation direction of the first diffracted ray is the same as the propagation direction of the second diffracted ray.
9. The optical waveguide assembly as described in any one of claims 1 to 8, characterized in that, The coupling grating is a two-dimensional grating, comprising a symmetrically distributed first sub-coupling grating and a second sub-coupling grating; the first sub-coupling grating is used to receive a portion of the first diffracted light and deflect a portion of the first diffracted light to the second sub-coupling grating; the second sub-coupling grating is used to diffract a portion of the first diffracted light from the waveguide substrate; the second sub-coupling grating is used to receive another portion of the first diffracted light and deflect another portion of the first diffracted light to the first sub-coupling grating; the first sub-coupling grating is used to diffract another portion of the first diffracted light from the waveguide substrate.
10. A near-eye display device, characterized in that, It includes an image source and an optical waveguide assembly as described in any one of claims 1 to 9, wherein the optical waveguide assembly is located on the light-emitting side of the image source.