Optical waveguides and near-eye display devices
By introducing a hybrid optical waveguide structure combining geometric reflection and diffraction into the optical waveguide, and replacing the transition pupil region with a diffraction grating region, the problem of reducing manufacturing complexity while improving optical performance in optical waveguides is solved, achieving high luminous efficiency, color uniformity, and low privacy leakage.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHUHAI MOJIE TECH CO LTD
- Filing Date
- 2026-04-01
- Publication Date
- 2026-06-30
AI Technical Summary
While improving optical performance, existing optical waveguides have difficulty reducing manufacturing complexity, especially in suppressing rainbow effects and privacy leaks.
A hybrid optical waveguide structure combining geometric reflection and diffraction is adopted. By setting diffraction grating regions on the first and second surfaces of the optical waveguide, and combining them with coupling-in and coupling-out reflection surfaces, a hybrid optical waveguide combining geometric reflection and diffraction is formed. The diffraction grating regions are used to replace the difficult-to-process transition pupil expansion regions, thereby reducing the complexity of the manufacturing process.
It improves the optical performance of optical waveguides, such as high luminous efficiency, color uniformity, and low privacy leakage, while reducing the complexity of the manufacturing process and reducing manufacturing steps.
Smart Images
Figure CN122307813A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of near-eye display technology, and more particularly to an optical waveguide and near-eye display device. Background Technology
[0002] Near-eye display devices can include augmented reality (AR) devices, mixed reality (MR) devices, and so on. Near-eye display devices can utilize optical waveguides to achieve their near-eye display function.
[0003] However, in related technologies, optical waveguides often suffer from the inability to simultaneously improve their optical performance while reducing the complexity of their manufacturing processes. For example, they cannot simultaneously enhance luminous efficacy, color uniformity, suppress rainbow effects, and minimize privacy leaks while reducing manufacturing complexity. Therefore, improvements to optical waveguides are urgently needed. Summary of the Invention
[0004] This application provides an optical waveguide and a near-eye display device, which aims to improve the optical effect of the optical waveguide while reducing the complexity of the manufacturing process of the optical waveguide.
[0005] In a first aspect, this application provides an optical waveguide, the optical waveguide comprising: A waveguide substrate, the waveguide substrate including a first surface and a second surface opposite each other in the vertical direction; A light coupling region, the light coupling region including a coupling reflective surface, the light coupling region being disposed between the first surface and the second surface; The light-emitting region includes at least one emitting reflective surface, the light-emitting region is disposed between the first surface and the second surface, and one of the emitting reflective surfaces is disposed adjacent to the emitting reflective surface in the horizontal direction; A diffraction grating region, the diffraction grating region including a diffraction grating, the diffraction grating region being disposed on at least one of the first surface and the second surface, and the first projection of the diffraction grating region on the first surface at least partially overlapping with the second projection of the light coupling region on the first surface, and / or the first projection of the diffraction grating region on the second surface at least partially overlapping with the second projection of the light coupling region on the second surface; After the light is coupled into the waveguide substrate by the coupling reflection surface, it is transmitted to the coupling reflection surface after being acted upon by the diffraction grating, and then coupled out of the waveguide substrate by the coupling reflection surface.
[0006] Secondly, this application provides a near-eye display device, the near-eye display device including the aforementioned optical waveguide.
[0007] This application provides an optical waveguide and a near-eye display device. The waveguide substrate includes a first surface and a second surface facing each other in the vertical direction. A light-introducing region and a light-outtroducing region are disposed between the first and second surfaces. A diffraction grating region is disposed on at least one of the first and second surfaces. The light-introducing region includes an introducing reflective surface, the light-outtroducing region includes at least one outtroducing reflective surface, and the diffraction grating region includes a diffraction grating. Thus, the optical waveguide incorporates both geometric reflection and diffraction waveguides, essentially constituting a hybrid geometric reflection and diffraction waveguide. This hybrid waveguide possesses the optical effects of a geometric waveguide, such as high luminous efficiency, good color uniformity, suppression of rainbow patterns, and low privacy leakage, as well as the optical effects of a diffraction waveguide, such as ease of manufacturing, thereby improving the overall optical performance of the waveguide. Furthermore, a diffraction grating region is provided in the optical waveguide, and the first projection of the diffraction grating region on the first surface at least partially overlaps with the second projection of the light coupling region on the first surface, and / or the first projection of the diffraction grating region on the second surface at least partially overlaps with the second projection of the light coupling region on the second surface. This is equivalent to expanding the one-dimensional geometric optical waveguide into a two-dimensional pupil-expanding hybrid optical waveguide. Compared to conventional two-dimensional geometric optical waveguides, the difficult-to-process transition pupil-expanding portion in a two-dimensional geometric optical waveguide can be replaced with a diffraction grating region, which helps to reduce the manufacturing complexity of the optical waveguide. Based on this, the optical waveguide in this application can improve the optical performance of the optical waveguide while reducing the manufacturing complexity of the optical waveguide. Attached Figure Description
[0008] Figure 1 This is a schematic diagram of the structure of a one-dimensional geometric optical waveguide involved in the related technology; Figure 2 This is a schematic diagram of the structure of a two-dimensional pupil-expanding geometric optical waveguide involved in the relevant technology; Figure 3 This is a schematic diagram of the structure of a hybrid optical waveguide involving geometric reflection and diffraction in related technologies. Figure 4 This is a schematic diagram of the structure of an optical waveguide provided in an embodiment of this application; Figure 5 This is a cross-sectional view of an optical waveguide according to an embodiment of this application; Figure 6 This is a schematic diagram of the structure of an optical waveguide according to another embodiment of this application; Figure 7 This is a schematic diagram of the structure of an optical waveguide according to another embodiment of this application; Figure 8 This is a cross-sectional view of an optical waveguide according to another embodiment of this application; Figure 9 This is a schematic diagram of the structure of a near-eye display device provided in an embodiment of this application.
[0009] Explanation of reference numerals in the attached figures: 10, near-eye display device; 100, optical waveguide; 110, waveguide substrate; 111, first surface; 112, second surface; 120, light coupling region; 121, coupling reflection surface; 130, light coupling out region; 131, coupling reflection surface; 140, diffraction grating region; 141, diffraction grating; 1411, first diffraction grating; 1412, second diffraction grating. Detailed Implementation
[0010] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0011] The flowchart shown in the attached diagram is for illustrative purposes only and does not necessarily include all content and operations / steps, nor does it necessarily have to be performed in the described order. For example, some operations / steps can be broken down, combined, or partially merged, so the actual execution order may change depending on the actual situation.
[0012] In related technologies, such as Figure 1 As shown, a one-dimensional geometric waveguide includes an input reflecting surface and multiple output beam-splitting surfaces. Due to the one-dimensional pupil expansion method, it is difficult to expand the one-dimensional geometric waveguide in the vertical eyebox region. Furthermore, the one-dimensional geometric waveguide relies on increasing the longitudinal coupling dimension of the optomechanical system to meet certain eyebox requirements. Therefore, developing a two-dimensional pupil-expanding geometric waveguide based on the one-dimensional geometric waveguide becomes an inevitable path.
[0013] In related technologies, such as Figure 2As shown, compared to one-dimensional geometric waveguides, two-dimensional pupil-expanding geometric waveguides also include a turning pupil-expanding region. This region comprises multiple reflective beam-splitting surfaces. These surfaces can also be called turning pupil-expanding beam-splitting surfaces, turning beam-splitting surfaces, etc. These turning beam-splitting surfaces are perpendicular to the waveguide surface of the two-dimensional pupil-expanding geometric waveguide and function as turning pupils and redirecting light rays. Because the turning beam-splitting surfaces, perpendicular to the waveguide surface, perform both pupil expansion and beam redirection, the manufacturing difficulty of these surfaces increases dramatically, resulting in persistently high production costs for two-dimensional pupil-expanding geometric waveguides. Furthermore, the addition of the turning pupil-expanding region necessitates an increase in the size of the eyebox when a larger field of view is required, hindering the lightweight design of two-dimensional pupil-expanding geometric waveguides. Consequently, applying two-dimensional pupil-expanding geometric waveguides to near-eye display devices impedes their lightweight design. Compared to two-dimensional pupil-expanding geometric waveguides, two-dimensional grating diffraction waveguides can utilize the coupling and pupil-expanding principle of two-dimensional gratings to obtain a larger eyebox than the aforementioned two-dimensional pupil-expanding geometric waveguides.
[0014] In related technologies, to reduce the fabrication difficulty of two-dimensional pupil-expanding geometric waveguides, the bend splitting surface of the two-dimensional pupil-expanding geometric waveguide is replaced with a diffraction grating, resulting in a hybrid geometric reflection and diffraction waveguide. The diffraction grating is then used for light redirection and expansion. For example... Figure 3 As shown, the bend splitting surface of the geometric reflection and diffraction hybrid waveguide is replaced by a diffraction grating, as shown in gratings EPE1 and EPE2. However, during the fabrication of gratings EPE1 and EPE2, angular errors are prone to occur in the geometric reflection and diffraction hybrid waveguide, which adversely affects the optical performance of the waveguide.
[0015] Therefore, it is urgent to improve the optical waveguide 100 in order to enhance its optical performance while reducing the complexity of its manufacturing process.
[0016] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.
[0017] Please see Figure 4 , Figure 4 This is a schematic diagram of the structure of an optical waveguide 100 provided in an embodiment of this application.
[0018] like Figure 4 As shown, the optical waveguide 100 includes a waveguide substrate 110, a light coupling region 120, a light coupling out region 130, and a diffraction grating region 140.
[0019] The waveguide substrate 110 includes a first surface 111 and a second surface 112 that are opposite each other in the vertical direction.
[0020] The light coupling region 120 includes a coupling reflection surface 121, and the light coupling region 120 is disposed between the first surface 111 and the second surface 112.
[0021] The light-emitting region 130 includes at least one emitting reflective surface 131. The light-emitting region 130 is disposed between the first surface 111 and the second surface 112, and one of the emitting reflective surfaces 131 and the receiving reflective surface 121 are arranged adjacent to each other in the horizontal direction.
[0022] The diffraction grating region 140 includes a diffraction grating 141. The diffraction grating region 140 is disposed on at least one of the first surface 111 and the second surface 112. The first projection of the diffraction grating region 140 on the first surface 111 at least partially overlaps with the second projection of the light coupling region 130 on the first surface 111, and / or the first projection of the diffraction grating region 140 on the second surface 112 at least partially overlaps with the second projection of the light coupling region 130 on the second surface 112.
[0023] After the light is coupled into the waveguide substrate 110 by the coupling reflection surface 121, it is transmitted to the coupling reflection surface 131 by the action of the diffraction grating 141, and then coupled out of the waveguide substrate 110 by the coupling reflection surface 131.
[0024] like Figure 4 As shown, the waveguide substrate 110 of the optical waveguide 100 includes a first surface 111 and a second surface 112 that are opposite each other in the vertical direction. A light coupling region 120 and a light coupling region 130 are disposed between the first surface 111 and the second surface 112. A diffraction grating region 140 is disposed on at least one of the first surface 111 and the second surface 112. The light coupling region 120 includes a coupling reflection surface 121, the light coupling region 130 includes at least one coupling reflection surface 131, and the diffraction grating region 140 includes a diffraction grating 141. Thus, the optical waveguide 100 is provided with both a geometric reflection waveguide and a diffraction waveguide, which is equivalent to a hybrid geometric reflection and diffraction waveguide. Geometric reflection and diffraction waveguides can possess the optical effects of geometric waveguides, such as high optical efficiency, good color uniformity, suppression of rainbow patterns, and low privacy leakage, as well as the optical effects of diffraction waveguides, such as ease of manufacturing. This is beneficial for improving the optical performance of waveguide 100.
[0025] In some embodiments, the diffraction grating region 140 includes a diffraction grating 141 that is a one-dimensional (1D) grating.
[0026] In some embodiments, the diffraction grating region 140 may be disposed on at least one of the first surface 111 and the second surface 112. The first surface 111 may serve as the world side corresponding to the optical waveguide 100, and the second surface 112 may serve as the human eye side corresponding to the optical waveguide 100. However, this is not a limitation; the first surface 111 may serve as the human eye side corresponding to the optical waveguide 100, and the second surface 112 may serve as the world side corresponding to the optical waveguide 100. No limitation is imposed here.
[0027] like Figure 5 As shown in (a), the diffraction grating region 140 can be disposed on the first surface 111. Figure 5 As shown in (b), the diffraction grating region 140 can be disposed on the second surface 112. Figure 5 As shown in (c), the diffraction grating region 140 can be disposed on either the first surface 111 or the second surface 112.
[0028] For example, the diffraction grating region 140 includes a first diffraction grating 1411 and a second diffraction grating 1412, the first diffraction grating 1411 being disposed on the first surface 111 and the second diffraction grating 1412 being disposed on the second surface 112.
[0029] like Figure 5 As shown in (c), for the first diffraction grating 1411 disposed on the first surface 111, if the first sub-projection of the first diffraction grating 1411 on the first surface 111 at least partially overlaps with the second projection of the light coupling region 130 on the first surface 111, it can be determined that the first diffraction grating 1411 and the light coupling region 130 at least partially overlap on the first surface 111, thereby causing the first projection of the diffraction grating region 140 on the first surface 111 and the second projection of the light coupling region 130 on the first surface 111 to at least partially overlap. However, this is not limited to this; if the first sub-projection of the first diffraction grating 1411 on the second surface 112 at least partially overlaps with the second projection of the light coupling region 130 on the second surface 112, it can be determined that the first diffraction grating 1411 and the light coupling region 130 on the second surface 112 to at least partially overlap, thereby causing the first projection of the diffraction grating region 140 on the second surface 112 and the second projection of the light coupling region 130 on the second surface 112 to at least partially overlap.
[0030] like Figure 5As shown in (c), for the second diffraction grating 1412 disposed on the second surface 112, if the second sub-projection of the second diffraction grating 1412 on the first surface 111 at least partially overlaps with the second projection of the light coupling region 130 on the first surface 111, it can be determined that the second diffraction grating 1412 and the light coupling region 130 at least partially overlap on the first surface 111, thereby causing the first projection of the diffraction grating region 140 on the first surface 111 to at least partially overlap with the second projection of the light coupling region 130 on the first surface 111. However, this is not the only possibility; if the second sub-projection of the second diffraction grating 1412 on the second surface 112 at least partially overlaps with the second projection of the light coupling region 130 on the second surface 112, it can be determined that the second diffraction grating 1412 and the light coupling region 130 at least partially overlap on the second surface 112, thereby causing the first projection of the diffraction grating region 140 on the second surface 112 to at least partially overlap with the second projection of the light coupling region 130 on the second surface 112.
[0031] For example, the first sub-projection of the first diffraction grating 1411 on the first surface 111 at least partially overlaps with the second sub-projection of the second diffraction grating 1412 on the first surface 111; and / or, the first sub-projection of the first diffraction grating 1411 on the second surface 112 at least partially overlaps with the second sub-projection of the second diffraction grating 1412 on the second surface 112.
[0032] For example, when the first diffraction grating 1411 is disposed on the first surface 111 and the second diffraction grating 1412 is disposed on the second surface 112, since both the first diffraction grating 1411 and the second diffraction grating 1412 at least partially overlap with the light coupling region 130 on the first surface 111 and / or the second surface 112, it can be ensured that the first sub-projection of the first diffraction grating 1411 on the first surface 111 and the second sub-projection of the second diffraction grating 1412 on the first surface 111 at least partially overlap; and / or, the first sub-projection of the first diffraction grating 1411 on the second surface 112 and the second sub-projection of the second diffraction grating 1412 on the second surface 112 at least partially overlap; The second sub-projection of the grating 1412 on the second surface 112 at least partially overlaps, thereby causing the first projection of the diffraction grating region 140 on the first surface 111 to at least partially overlap with the second projection of the light coupling region 130 on the first surface 111, and / or the first projection of the diffraction grating region 140 on the second surface 112 to at least partially overlap with the second projection of the light coupling region 130 on the second surface 112. This is beneficial to improving the design flexibility of the diffraction grating region 140 while ensuring that the diffraction grating region 140 and the light coupling region 130 at least partially overlap on the first surface 111 and / or the second surface 112.
[0033] A diffraction grating region 140 is provided in the optical waveguide 100, and the first projection of the diffraction grating region 140 on the first surface 111 at least partially overlaps with the second projection of the light coupling region 130 on the first surface 111, and / or the first projection of the diffraction grating region 140 on the second surface 112 at least partially overlaps with the second projection of the light coupling region 130 on the second surface 112. This is equivalent to expanding the one-dimensional geometric optical waveguide into a two-dimensional pupil-expanding hybrid optical waveguide. Compared with conventional two-dimensional geometric optical waveguides, the difficult-to-process bend pupil-expanding portion in the two-dimensional geometric optical waveguide can be replaced with the diffraction grating region 140, which helps to reduce the manufacturing process complexity of the optical waveguide 100. Based on this, the optical waveguide 100 of this application can improve the optical effect of the optical waveguide 100 while reducing the manufacturing process complexity of the optical waveguide 100.
[0034] Furthermore, a diffraction grating region 140 is provided in the optical waveguide 100. The diffraction grating region 140 is disposed on at least one of the first surface 111 and the second surface 112. If the first projection of the diffraction grating region 140 on the first surface 111 at least partially overlaps with the second projection of the light coupling region 130 on the first surface 111, and / or the first projection of the diffraction grating region 140 on the second surface 112 at least partially overlaps with the second projection of the light coupling region 130 on the second surface 112, it can be determined that the diffraction grating region 140 and the light coupling region 130 disposed in the optical waveguide 100 at least partially overlap in the vertical direction. This diffraction grating region 140 is insensitive to the processing angle error of the diffraction grating 141. For example, regardless of whether the diffraction grating region 140 is disposed on the first surface 111, or on the second surface 112, or on both the first surface 111 and the second surface 112, even if the diffraction grating 141 included in the diffraction grating region 140 of the optical waveguide 100 has a corresponding angular error when processing it, this application can still ensure that the diffraction grating region 140 disposed in the optical waveguide 100 and the light coupling region 130 overlap at least partially in the vertical direction. This helps to reduce the angular error of the diffraction grating region 140, which would have an adverse effect on the optical effect of the optical waveguide 100. This is beneficial to improving the optical effect of the optical waveguide 100 while reducing the manufacturing process complexity of the optical waveguide 100.
[0035] like Figure 4As shown, when light is incident on the coupling reflection surface 121 included in the light coupling region 120, the coupling reflection surface 121 can couple the light into the waveguide substrate 110. After passing through the diffraction grating 141 included in the diffraction grating region 140, the light is transmitted to the coupling reflection surface 131 included in the light coupling region 130, and then coupled out of the waveguide substrate 110 after passing through the coupling reflection surface 131. Based on this, the optical waveguide 100 has a display function. When the optical waveguide 100 is applied to the near-eye display device 10, the optical waveguide 100 can enable the near-eye display device 10 to realize the near-eye display function.
[0036] In some embodiments, the angle difference between the light rays coupled out of the light ray coupled out of the light ray coupled into ...
[0037] When designing the optical waveguide 100, including the light output region 130 and the light input region 120, the angle difference between the light output from the light output region 130 and the light incident on the light input region 120 can be arbitrarily updated, while keeping the angle difference between the light output from the light output region 130 and the light incident on the light input region 120 less than or equal to a preset angle threshold.
[0038] The preset angle threshold can be pre-set or set by the user. For example, the preset angle threshold may include at least one of 0°, 1°, 5°, etc., without limitation.
[0039] In some exemplary implementations, such as Figure 6 As shown, the insertion angle of the light by the insertion reflection surface 121 of the light insertion region 120 is equal to the insertion angle of the light by the insertion reflection surface 131 of the light extraction region 130. Consequently, the insertion direction of the light by the insertion reflection surface 121 of the light insertion region 120 is equal to the insertion direction of the light by the insertion reflection surface 131 of the light extraction region 130. At this point, the diffraction grating region 140 can be considered decoupled from both the light insertion region 120 and the light extraction region 130. This further enhances the design freedom regarding the size and position of the eyebox of the light extraction region 130 within the optical waveguide 100, and also helps suppress the increase of rainbow patterns.
[0040] In some embodiments, the area of the first projection of the diffraction grating region 140 on the first surface 111 is greater than or equal to the area of the second projection of the light-out region 130 on the first surface 111; and / or, the area of the first projection of the diffraction grating region 140 on the second surface 112 is greater than or equal to the area of the second projection of the light-out region 130 on the second surface 112.
[0041] For example, when designing the diffraction grating region 140 included in the optical waveguide 100, the area of the first projection of the diffraction grating region 140 on the first surface 111 can be set to be greater than or equal to the area of the second projection of the light coupling region 130 on the first surface 111. This increases the possibility that the diffraction grating region 140 and the light coupling region 130 will at least partially overlap on the first surface 111, thereby helping to reduce the area occupied by the diffraction grating region 140 and the light coupling region 130 in the horizontal direction of the waveguide substrate 110, which in turn helps to reduce the volume of the optical waveguide 100.
[0042] Accordingly, when designing the diffraction grating region 140 included in the optical waveguide 100, the area of the first projection of the diffraction grating region 140 on the second surface 112 can be set to be greater than or equal to the area of the second projection of the light coupling region 130 on the second surface 112, so as to increase the possibility that the diffraction grating region 140 and the light coupling region 130 at least partially overlap on the second surface 112, thereby helping to reduce the area occupied by the diffraction grating region 140 and the light coupling region 130 in the horizontal direction of the waveguide substrate 110, which is beneficial to reducing the volume of the optical waveguide 100.
[0043] In some exemplary embodiments, when the diffraction grating region 140 includes a first diffraction grating 1411 and a second diffraction grating 1412, the area of the first sub-projection of the first diffraction grating 1411 on the first surface 111 is greater than or equal to the area of the second projection of the light coupling region 130 on the first surface 111; and / or, the area of the first sub-projection of the first diffraction grating 1411 on the second surface 112 is greater than or equal to the area of the second projection of the light coupling region 130 on the second surface 112; and / or, the area of the second sub-projection of the second diffraction grating 1412 on the first surface 111 is greater than or equal to the area of the second projection of the light coupling region 130 on the first surface 111; and / or, the area of the second sub-projection of the second diffraction grating 1412 on the second surface 112 is greater than or equal to the area of the second projection of the light coupling region 130 on the second surface 112. Therefore, the arrangement of the first diffraction grating 1411 and the second diffraction grating 1412 can increase the possibility that the diffraction grating region 140 and the light coupling region 130 will at least partially overlap on the second surface 112, which is conducive to reducing the area occupied by the diffraction grating region 140 and the light coupling region 130 in the horizontal direction of the waveguide substrate 110, and thus helps to reduce the volume of the optical waveguide 100.
[0044] In some embodiments, the area of the first projection of the diffraction grating region 140 on the first surface 111 is less than or equal to the area of the first surface 111; and / or, the area of the first projection of the diffraction grating region 140 on the second surface 112 is less than or equal to the area of the second surface 112.
[0045] For example, if the area of the first projection of the diffraction grating region 140 on the first surface 111 is less than or equal to the area of the first surface 111, the area of the first projection of the diffraction grating region 140 on the first surface 111 can be greater than or equal to the area of the second projection of the light coupling region 130 on the first surface 111, and less than or equal to the area of the first surface 111. This is beneficial to ensure that the diffraction grating region 140 and the light coupling region 130 at least partially overlap on the first surface 111.
[0046] Accordingly, if the area of the first projection of the diffraction grating region 140 on the second surface 112 is less than or equal to the area of the second surface 112, the area of the first projection of the diffraction grating region 140 on the second surface 112 can, for example, be greater than or equal to the area of the second projection of the light coupling region 130 on the second surface 112, and less than or equal to the area of the second surface 112. This is beneficial to ensure that the diffraction grating region 140 and the light coupling region 130 at least partially overlap on the second surface 112.
[0047] In some exemplary embodiments, when the diffraction grating region 140 includes a first diffraction grating 1411 and a second diffraction grating 1412, the area of the first sub-projection of the first diffraction grating 1411 on the first surface 111 is less than or equal to the area of the first surface 111; and / or, the area of the first sub-projection of the first diffraction grating 1411 on the second surface 112 is less than or equal to the area of the second surface 112; and / or, the area of the second sub-projection of the second diffraction grating 1412 on the first surface 111 is less than or equal to the area of the first surface 111; and / or, the area of the second sub-projection of the second diffraction grating 1412 on the second surface 112 is less than or equal to the area of the second surface 112. Thus, the arrangement of the first diffraction grating 1411 and the second diffraction grating 1412 can increase the possibility that the diffraction grating region 140 and the light coupling region 130 at least partially overlap on the second surface 112.
[0048] In some embodiments, the grating period of the diffraction grating 141 is less than or equal to 380 nm and greater than or equal to 225 nm.
[0049] For example, the grating period of the diffraction grating 141 may include one of 225nm, 230nm, 247nm, 266nm, 285nm, 300nm, 310nm, 317nm, and 380nm.
[0050] Of course, this is not the only limitation. The grating period of the diffraction grating 141 can be greater than or equal to 225 nm and less than or equal to 317 nm. Alternatively, the grating period of the diffraction grating 141 can be greater than or equal to 230 nm and less than or equal to 380 nm. Or, the grating period of the diffraction grating 141 can be greater than or equal to 247 nm and less than or equal to 310 nm, and so on. No restrictions are imposed here.
[0051] When the grating period of diffraction grating 141 is less than or equal to 380 nm and greater than or equal to 225 nm, it can be determined that the grating period of diffraction grating 141 is less than the wavelength of visible light. and close to The diffraction grating 141 can exhibit the anti-reflective properties of a grating. When the diffraction grating region 140 and the light-coupled region 120 at least partially overlap on the first surface 111 and / or the second surface 112, the diffraction grating region 140 can achieve higher ambient light transmittance, thereby effectively improving the overall transmittance of the light-coupled region 120, the light-coupled region 130, and the diffraction grating region 140 included in the optical waveguide 100, which is beneficial to improving the optical effect of the optical waveguide 100. For example, the diffraction grating region 140 can improve transmittance and suppress rainbow patterns. Correspondingly, since the diffraction grating 141 included in the diffraction grating region 140 does not have a coupling effect and does not produce coupling diffraction, it can maintain low privacy leakage light, thereby helping to suppress privacy leakage.
[0052] In some embodiments, the grating period of the diffraction grating 141 is less than 300 nm.
[0053] For example, the grating period of the diffraction grating 141 can be greater than or equal to 225 nm and less than 300 nm. In particular, the grating period of the diffraction grating 141 may include one of 225 nm, 230 nm, 247 nm, 266 nm, 285 nm, 290 nm, and 295 nm.
[0054] Of course, this is not the only limitation. The grating period of the diffraction grating 141 can be greater than or equal to 225 nm and less than or equal to 295 nm. Alternatively, the grating period of the diffraction grating 141 can be greater than or equal to 230 nm and less than 300 nm. Or, the grating period of the diffraction grating 141 can be greater than or equal to 247 nm and less than or equal to 290 nm, and so on. No restrictions are imposed here.
[0055] Because green light, compared to other colors of visible light, has advantages such as being the brightest visible to the human eye, having the least physical dispersion, being the easiest to manufacture, and having the lowest power consumption, the grating period of the diffraction grating 141 can be determined by considering the wavelength of green light. For example, the grating period of the diffraction grating 141 can be designed to be less than 300 nm. When the grating period of the diffraction grating 141 is less than 300 nm, it can be determined that the grating period of the diffraction grating 141 is less than the wavelength of green light. and close to The diffraction grating 141 can exhibit the anti-reflection properties of a grating. When the diffraction grating region 140 and the light-exiting region 130 at least partially overlap on the first surface 111 and / or the second surface 112, the diffraction grating region 140 can obtain higher ambient light transmittance, thereby effectively improving the overall transmittance of the light-input region 120, the light-exiting region 130, and the diffraction grating region 140 included in the optical waveguide 100, which is beneficial to improving the optical effect of the optical waveguide 100.
[0056] Furthermore, when the grating period of the diffraction grating 141 is less than 300nm, the optical waveguide 100 can effectively suppress the rainbow effect caused by the diffraction grating region in the related technology, which is beneficial to suppressing or even eliminating the rainbow effect from the diffraction grating region, thereby improving the optical effect of the optical waveguide 100.
[0057] Furthermore, when determining the grating period of the diffraction grating 141 by combining the wavelength of green light, relevant personnel can leave corresponding optimization space for other colors of visible light, which is conducive to further improving the optical effect of the optical waveguide 100.
[0058] For example, when designing the diffraction grating region 140 included in the optical waveguide 100, the diffraction grating region 140 can be designed by combining the grating period of the diffraction grating 141 in the diffraction grating region 140 and the area of the first projection of at least one of the first surface 111 and the second surface 112 of the diffraction grating region 140.
[0059] In some embodiments, the grating period of the diffraction grating 141 is less than or equal to 380 nm and greater than or equal to 225 nm, and the area of the first projection of the diffraction grating region 140 on the first surface 111 is less than or equal to the area of the first surface 111; and / or, the area of the first projection of the diffraction grating region 140 on the second surface 112 is less than or equal to the area of the second surface 112.
[0060] For example, the diffraction grating region 140 includes a first diffraction grating 1411 and a second diffraction grating 1412. The grating periods of the first diffraction grating 1411 and the second diffraction grating 1412 are each less than or equal to 380 nm and greater than or equal to 225 nm. The area of the first sub-projection of the first diffraction grating 1411 on the first surface 111 is less than or equal to the area of the first surface 111; and / or, the area of the first sub-projection of the first diffraction grating 1411 on the second surface 112 is less than or equal to the area of the second surface 112; and / or, the area of the second sub-projection of the second diffraction grating 1412 on the first surface 111 is less than or equal to the area of the second surface 112; and / or, the area of the second sub-projection of the second diffraction grating 1412 on the second surface 112 is less than or equal to the area of the second surface 112.
[0061] like Figure 7 as well as Figure 8 As shown, when the area of the first sub-projection of the first diffraction grating 1411 on the first surface 111 is equal to the area of the first surface 111, the area of the first sub-projection of the first diffraction grating 1411 on the second surface 112 is equal to the area of the second surface 112, and / or the area of the second sub-projection of the second diffraction grating 1412 on the second surface 112 is equal to the area of the second surface 112, and / or the area of the second sub-projection of the second diffraction grating 1412 on the first surface 111 is equal to the area of the first surface 111, the optical waveguide 100 is equivalent to having a diffraction grating 141 arranged on the entire surface of at least one of the first surface 111 and the second surface 112 of the waveguide substrate 110. When the grating periods of the first diffraction grating 1411 and the second diffraction grating 1412 are both less than or equal to 380 nm and greater than or equal to 225 nm, both the first diffraction grating 1411 and the second diffraction grating 1412 have anti-reflection and anti-reflection properties. This means that when the first diffraction grating 1411 is arranged on the entire first surface 111 of the waveguide substrate 110 and the second diffraction grating 1412 is arranged on the entire second surface 112 of the waveguide substrate 110, the optical waveguide 100 can obtain extremely high transmittance without double-sided AR coating. This helps to reduce defects such as trailing and ghosting introduced by coating in the optical waveguide 100, and at the same time, it can reduce the coating process, thereby improving the optical effect of the optical waveguide 100 while reducing the complexity of the manufacturing process of the optical waveguide 100.
[0062] The setting of the diffraction grating region 140 is equivalent to improving the transmittance of the entire waveguide surface, that is, the first surface 111 or the second surface 112 of the waveguide substrate 110, so that the first surface 111 or the second surface 112 of the waveguide substrate 110 can expand the light, which is beneficial to improving the uniformity of the light, and thus beneficial to improving the optical effect of the optical waveguide 100.
[0063] Furthermore, when the grating period of the diffraction grating 141 is less than or equal to 380 nm and greater than or equal to 225 nm, the optical waveguide 100 can effectively suppress the rainbow effect caused by the diffraction grating region in related technologies. This is beneficial for suppressing or even eliminating the rainbow effect originating from the diffraction grating region, thereby improving the optical performance of the optical waveguide 100. In some embodiments, an adhesive layer is provided between the light coupling region 130 and the diffraction grating region 140.
[0064] For example, a diffraction grating region 140 can be disposed in the optical waveguide 100 by spin-coating photoresist, placing the diffraction grating region 140 on at least one of the first surface 111 and the second surface 112 of the waveguide substrate 110 included in the optical waveguide 100. When the light-emitting region 130 is disposed between the first surface 111 and the second surface 112, and the diffraction grating region 140 and the light-emitting region 130 at least partially overlap on the first surface 111 and / or the second surface 112, an adhesive layer can be formed between the light-emitting region 130 and the diffraction grating region 140. The adhesive layer can improve bonding defects between at least one coupling reflective surface 131 included in the grating coupling region. For example, the adhesive layer can utilize its own adhesive filling properties to fill the beam-splitting adhesive groove in at least one coupling reflective surface 131 of the grating coupling region, thereby helping to improve the display ghosting problem of the optical waveguide 100 and thus improving the optical effect of the optical waveguide 100.
[0065] The optical waveguide 100 provided in the above embodiment includes a first surface 111 and a second surface 112 that are opposite each other in the vertical direction on the waveguide substrate 110 of the optical waveguide 100. A light coupling region 120 and a light coupling region 130 are disposed between the first surface 111 and the second surface 112. A diffraction grating region 140 is disposed on at least one of the first surface 111 and the second surface 112. The light coupling region 120 includes a coupling reflection surface 121, the light coupling region 130 includes at least one coupling reflection surface 131, and the diffraction grating region 140 includes a diffraction grating 141. In this way, the optical waveguide 100 is provided with both a geometric reflection waveguide and a diffraction waveguide, which is equivalent to a hybrid optical waveguide of geometric reflection and diffraction. The hybrid optical waveguide combining geometric reflection and diffraction can possess both the optical effects of a geometric waveguide (such as high luminous efficiency, good color uniformity, suppression of rainbow patterns, and low privacy leakage) and the optical effects of a diffraction waveguide (such as ease of manufacturing), thus improving the optical performance of the optical waveguide 100. Furthermore, the optical waveguide 100 includes a diffraction grating region 140, and the first projection of the diffraction grating region 140 on the first surface 111 at least partially overlaps with the second projection of the light coupling region 130 on the first surface 111, and / or the first projection of the diffraction grating region 140 on the second surface 112 at least partially overlaps with the second projection of the light coupling region 130 on the second surface 112. This effectively expands a one-dimensional geometric waveguide into a two-dimensional pupil-expanding hybrid optical waveguide. Compared to a conventional two-dimensional geometric waveguide, the difficult-to-process transition pupil-expanding portion in a two-dimensional geometric waveguide can be replaced with the diffraction grating region 140, which helps reduce the manufacturing complexity of the optical waveguide 100. Based on this, the optical waveguide 100 in this application can improve the optical effect of the optical waveguide 100 while reducing the manufacturing process complexity of the optical waveguide 100.
[0066] Please see Figure 9 , Figure 9 This is a schematic diagram of the structure of a near-eye display device 10 provided in an embodiment of this application.
[0067] In some embodiments, the near-eye display device 10 includes an optical waveguide 100 as provided in any of the embodiments described above.
[0068] It should be understood that the optical waveguide 100 provided in any of the above embodiments includes a first surface 111 and a second surface 112 that are opposite each other in the vertical direction on the waveguide substrate 110 of the optical waveguide 100. A light coupling region 120 and a light coupling region 130 are disposed between the first surface 111 and the second surface 112. A diffraction grating region 140 is disposed on at least one of the first surface 111 and the second surface 112. The light coupling region 120 includes a coupling reflection surface 121, the light coupling region 130 includes at least one coupling reflection surface 131, and the diffraction grating region 140 includes a diffraction grating 141. In this way, the optical waveguide 100 is provided with both a geometric reflection waveguide and a diffraction waveguide, which is equivalent to a hybrid geometric reflection and diffraction waveguide. The hybrid optical waveguide combining geometric reflection and diffraction can possess both the optical effects of a geometric waveguide (such as high luminous efficiency, good color uniformity, suppression of rainbow patterns, and low privacy leakage) and the optical effects of a diffraction waveguide (such as ease of manufacturing), thus improving the optical performance of the optical waveguide 100. Furthermore, the optical waveguide 100 includes a diffraction grating region 140, and the first projection of the diffraction grating region 140 on the first surface 111 at least partially overlaps with the second projection of the light coupling region 130 on the first surface 111, and / or the first projection of the diffraction grating region 140 on the second surface 112 at least partially overlaps with the second projection of the light coupling region 130 on the second surface 112. This effectively expands a one-dimensional geometric waveguide into a two-dimensional pupil-expanding hybrid optical waveguide. Compared to a conventional two-dimensional geometric waveguide, the difficult-to-process transition pupil-expanding portion in a two-dimensional geometric waveguide can be replaced with the diffraction grating region 140, which helps reduce the manufacturing complexity of the optical waveguide 100. Based on this, the optical waveguide 100 in this application can improve the optical performance of the optical waveguide 100 while reducing the complexity of its manufacturing process. The specific structure and implementation principle of the optical waveguide 100 included in the near-eye display device 10 can be found above and will not be described further here.
[0069] For example, the near-eye display device 10 includes AR devices, such as AR glasses, AR helmets, etc.; the near-eye display device 10 may also include mixed reality (MR) devices, such as MR glasses, MR helmets, etc., without limitation.
[0070] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. The above descriptions are merely specific implementations of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. An optical waveguide, characterized in that, The optical waveguide includes: A waveguide substrate, the waveguide substrate including a first surface and a second surface opposite each other in the vertical direction; A light coupling region, the light coupling region including a coupling reflective surface, the light coupling region being disposed between the first surface and the second surface; The light-emitting region includes at least one emitting reflective surface, the light-emitting region is disposed between the first surface and the second surface, and one of the emitting reflective surfaces is disposed adjacent to the emitting reflective surface in the horizontal direction; A diffraction grating region, the diffraction grating region including a diffraction grating, the diffraction grating region being disposed on at least one of the first surface and the second surface, and the first projection of the diffraction grating region on the first surface at least partially overlapping with the second projection of the light coupling region on the first surface, and / or the first projection of the diffraction grating region on the second surface at least partially overlapping with the second projection of the light coupling region on the second surface; After the light is coupled into the waveguide substrate by the coupling reflection surface, it is transmitted to the coupling reflection surface after being acted upon by the diffraction grating, and then coupled out of the waveguide substrate by the coupling reflection surface.
2. The optical waveguide according to claim 1, characterized in that, The area of the first projection of the diffraction grating region onto the first surface is greater than or equal to the area of the second projection of the light coupling region onto the first surface; and / or, The area of the first projection of the diffraction grating region on the second surface is greater than or equal to the area of the second projection of the light coupling region on the second surface.
3. The optical waveguide according to claim 1, characterized in that, The area of the first projection of the diffraction grating region onto the first surface is less than or equal to the area of the first surface; and / or, The area of the first projection of the diffraction grating region onto the second surface is less than or equal to the area of the second surface.
4. The optical waveguide according to claim 1, characterized in that, The diffraction grating region includes a first diffraction grating and a second diffraction grating, wherein the first diffraction grating is disposed on the first surface and the second diffraction grating is disposed on the second surface.
5. The optical waveguide according to claim 4, characterized in that, The first sub-projection of the first diffraction grating on the first surface at least partially overlaps with the second sub-projection of the second diffraction grating on the first surface; and / or, The first sub-projection of the first diffraction grating on the second surface at least partially overlaps with the second sub-projection of the second diffraction grating on the second surface.
6. The optical waveguide according to any one of claims 1 to 5, characterized in that, The grating period of the diffraction grating is less than or equal to 380 nm and greater than or equal to 225 nm.
7. The optical waveguide according to claim 6, characterized in that, The grating period of the diffraction grating is less than 300 nm.
8. The optical waveguide according to any one of claims 1 to 5, characterized in that, The angle difference between the light rays coupled out of the light coupling region and the light rays incident on the light coupling region is less than or equal to a preset angle threshold.
9. The optical waveguide according to any one of claims 1 to 5, characterized in that, An adhesive layer is provided between the light coupling region and the diffraction grating region.
10. A near-eye display device, characterized in that, Includes the optical waveguide as described in any one of claims 1 to 9.