Optical waveguide and near-eye display device
By using a curved waveguide substrate and a coupling grating with a different structure in the optical waveguide, the problem of increased device weight and size caused by refractive lenses in the prior art is solved, achieving clear imaging of external ambient light and virtual image light, and reducing the burden on near-eye display devices.
Patent Information
- Application Number
- CN202423321638.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-12-16
- Estimated Expiration
- 2034-12-31
AI Technical Summary
To accommodate users with refractive errors, existing near-eye display devices typically place refractive lenses on the side of the waveguide furthest from the eye, which increases the weight and size of the device and affects the wearing experience.
A waveguide substrate with a curved surface is used, and coupling gratings and multiple coupling gratings with different structures are set on it. By adjusting the transmission direction of external ambient light and virtual image light, it can be clearly imaged by the human eye without the need to add additional lens groups or optical adjustment elements.
It achieves refractive adjustment, ensuring clear imaging of both ambient light and virtual image light in the human eye, while reducing the weight and size of near-eye display devices.
Smart Images
Figure CN223679390U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of diffractive optical waveguide, in particular to an optical waveguide and a near-eye display device. BACKGROUND
[0002] The optical waveguide is widely used in the field of augmented reality (AR) and mixed reality (MR) due to its superior optical performance. In the related art, in order to adapt to users with myopia or hypermetropia, a dioptric lens is arranged on the side of the optical waveguide away from the human eye in the near-eye display device, and the dioptric lens is used to adjust the refraction of external environmental light, so that the external environmental light can be clearly imaged in the human eye after passing through the optical waveguide. However, this arrangement increases the weight and volume of the near-eye display device, and reduces the wearing experience of the user. SUMMARY
[0003] Embodiments of the present application provide an optical waveguide and a near-eye display device, which aims to achieve refraction adjustment while reducing the weight and volume of the near-eye display device.
[0004] In a first aspect, an optical waveguide is provided, comprising:
[0005] a waveguide substrate, the waveguide substrate having a curved surface;
[0006] an in-coupling grating, the in-coupling grating being arranged on the waveguide substrate, the in-coupling grating being configured to couple light into the waveguide substrate, so that the light propagates in the waveguide substrate; and
[0007] a plurality of out-coupling gratings, the plurality of out-coupling gratings being arranged on the curved surface, or the plurality of out-coupling gratings being arranged on a surface of the waveguide substrate opposite to the curved surface, the plurality of out-coupling gratings being configured to couple the light propagating in the waveguide substrate out of the waveguide substrate, and the plurality of out-coupling gratings having different structures.
[0008] Optionally, the plurality of out-coupling gratings have different grating periods.
[0009] Optionally, the grating period of the out-coupling grating is equal to the grating period of the in-coupling grating in the projection of the plane on which the in-coupling grating is arranged.
[0010] Optionally, the plurality of out-coupling gratings are uniformly arranged.
[0011] Optionally, the plurality of out-coupling gratings are arranged at intervals, or the plurality of out-coupling gratings are arranged in close contact.
[0012] Optionally, the light coupled out of the plurality of out-coupling gratings converges; or
[0013] The light rays coupled out by the plurality of the out-coupling gratings are divergent; or,
[0014] The transmission directions of the light rays coupled out by at least two of the out-coupling gratings are different.
[0015] The transmission directions of the light rays coupled out by at least two of the out-coupling gratings are the same.
[0016] Optionally, the out-coupling gratings are surface relief gratings or volume holographic gratings.
[0017] Optionally, the curved surface comprises a convex surface, and the plurality of the out-coupling gratings are arranged on the convex surface.
[0018] Optionally, the curved surface comprises a convex surface and a concave surface arranged oppositely, and the distance between the convex surface and the concave surface is equal.
[0019] In a second aspect, the embodiments of the present application further provide a near-eye display device, comprising the optical waveguide described above.
[0020] The embodiments of the present application provide an optical waveguide and a near-eye display device. The waveguide substrate has a curved surface. When external ambient light is transmitted to the curved surface, the curved surface can adjust the transmission direction of the external ambient light, so that when a user with ametropia wears the near-eye display device, the external ambient light can also be clearly imaged in the human eye. Meanwhile, the virtual image light transmitted in the near-eye display device is coupled into the waveguide substrate via the in-coupling grating, propagates in the waveguide substrate, and is finally coupled out via the out-coupling gratings arranged on the curved surface or the surface opposite to the curved surface. The out-coupling gratings are multiple, and the structures of the multiple out-coupling gratings are different, so that the multiple out-coupling gratings have different diffraction effects, the transmission direction of the coupled-out virtual image light can be adjusted, the coupled-out virtual image light is less affected by the curved surface, and can be finally clearly imaged in the human eye. The optical waveguide of the embodiments of the present application can realize refractive adjustment, so that the external ambient light and the virtual image light can be clearly imaged in the human eye, and there is no need to additionally add a lens group or an optical adjustment element in the near-eye display device, which is beneficial to reducing the weight and the volume of the near-eye display device. BRIEF DESCRIPTION OF DRAWINGS
[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort.
[0022] Figure 1 The structure schematic diagram of the near-eye display device provided by the embodiments of the present application;
[0023] Figure 2 For Figure 1 A schematic diagram of light propagation in a near-eye display device is provided.
[0024] Figure 3 A schematic diagram of a structure of an optical waveguide is provided for embodiments of the present application.
[0025] Figure 4 A schematic diagram of a structure of an in-coupling grating and an out-coupling grating is provided for embodiments of the present application.
[0026] Main reference signs:
[0027] 100, optical waveguide; 10, waveguide substrate; 10a, in-coupling region; 10b, out-coupling region; 20, in-coupling grating; 30, out-coupling grating;
[0028] 200, light engine; 300, lens module. DETAILED DESCRIPTION
[0029] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.
[0030] The flowcharts shown in the drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor do they have to be executed in the order described. For example, some operations / steps can be further decomposed, combined or partially merged, so the actual execution order can be changed according to the actual situation.
[0031] It should be understood that the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and the appended claims of the present application, the singular forms "a", "an" and "the" are intended to include the plural forms unless the context clearly indicates otherwise.
[0032] Some embodiments of the present application will be described in detail below with reference to the drawings. The following embodiments and features in the embodiments can be combined with each other as long as there is no conflict.
[0033] Please refer to Figure 1The embodiment of the present application provides a kind of optical waveguide, optical waveguide 100 includes waveguide substrate 10, in-coupling grating 20 and multiple out-coupling gratings 30.Waveguide substrate 10 has curved surface.In-coupling grating 20 is arranged in waveguide substrate 10, and in-coupling grating 20 is used to couple light into waveguide substrate 10, to make light propagate in waveguide substrate 10.Multiple out-coupling gratings 30 are arranged on curved surface, alternatively, multiple out-coupling gratings 30 are arranged on the surface of waveguide substrate 10 opposite to curved surface, and multiple out-coupling gratings 30 are used to couple light propagating in waveguide substrate 10 out of waveguide substrate 10, and the structure of multiple out-coupling gratings 30 is different.
[0034] It can be understood that the user with ametropia can transmit external environment light to human eye when using the near-eye display device with the optical waveguide 100 of the embodiment of the present application, and the curved surface of the waveguide substrate 10 can adjust the transmission direction of the external environment light when the external environment light passes through the curved surface of the waveguide substrate 10, so that the external environment light can be clearly imaged in the human eye.At the same time, the virtual image light is coupled into the waveguide substrate 10 through the in-coupling grating 20 and is transmitted in the waveguide substrate 10, and finally is coupled out through the out-coupling grating 30 arranged thereon.In order to reduce the influence of the virtual image light on the curved surface, multiple out-coupling gratings 30 are arranged on the curved surface or the surface opposite to the curved surface, and the structures of the multiple out-coupling gratings 30 are different, so that the multiple out-coupling gratings 30 have different diffraction effects, the transmission direction of the coupled-out light can be adjusted, and the coupled-out light can be clearly imaged in the human eye after being transmitted to the human eye.
[0035] The optical waveguide 100 of the embodiment of the present application can realize refractive adjustment when applied to the near-eye display device, so that the external environment light and the virtual image light can be clearly imaged in the human eye, and it is not necessary to additionally increase lens group or optical adjustment element in the near-eye display device, which is beneficial to reduce the weight and the size of the near-eye display device.
[0036] Illustratively, the waveguide substrate 10 can be made of glass, plastic or the like.
[0037] Illustratively, the in-coupling region 10a of the waveguide substrate 10 is provided with the in-coupling grating 20, and the in-coupling region 10a can have a plane and / or a curved surface, which can be adjusted according to actual conditions.
[0038] Illustratively, the in-coupling grating 20 can be one or more, and the in-coupling grating 20 can be a transmission grating or a reflection grating.
[0039] It can be understood that the out-coupling region 10b of the waveguide substrate 10 has a curved surface, and the multiple out-coupling gratings 30 are arranged on the curved surface of the out-coupling region 10b, but it is not limited that the out-coupling region 10b only has a curved surface.For example, the same side of the out-coupling region 10b of the waveguide substrate 10 can also have a plane connected with the curved surface, which can be adjusted according to actual requirements.
[0040] Optionally, the curved surface is a spherical surface or an aspherical surface.
[0041] For example, the curved surface of the out-coupling region 10b of the waveguide substrate 10 can be a spherical surface or an aspherical surface. In some embodiments, the curved surface of the out-coupling region 10b of the waveguide substrate 10 can include a convex surface protruding outwardly from the waveguide substrate 10, and the plurality of out-coupling gratings 30 can be arranged on the convex surface. In some embodiments, the curved surface of the out-coupling region 10b of the waveguide substrate 10 can include a concave surface recessed inwardly from the waveguide substrate 10, and the plurality of out-coupling gratings 30 can be arranged on the concave surface.
[0042] For example, as shown in FIG. 1, the curved surface of the out-coupling region 10b of the waveguide substrate 10 can include a convex surface 10a and a concave surface 10b. The convex surface 10a and the concave surface 10b can be arranged oppositely, and the distance between the convex surface 10a and the concave surface 10b can be equal. Figure 1 For example, as shown in FIG. 2, the curved surface of the out-coupling region 10b of the waveguide substrate 10 can include a convex surface 10a protruding outwardly from the waveguide substrate 10, and the plurality of out-coupling gratings 30 can be arranged on the convex surface 10a.
[0043] For example, as shown in FIG. 3, the curved surface of the out-coupling region 10b of the waveguide substrate 10 can include a concave surface 10b recessed inwardly from the waveguide substrate 10, and the plurality of out-coupling gratings 30 can be arranged on the concave surface 10b. Figure 4 For example, as shown in FIG. 4, the curved surface of the out-coupling region 10b of the waveguide substrate 10 can include a convex surface 10a and a concave surface 10b arranged oppositely, and the distance between the convex surface 10a and the concave surface 10b can be equal.
[0044] For example, as shown in FIG. 5, the curved surface of the out-coupling region 10b of the waveguide substrate 10 can include a convex surface 10a and a concave surface 10b arranged oppositely, and the distance between the convex surface 10a and the concave surface 10b can be equal.
[0045] Figure 1 For example, as shown in FIG. 6, the curved surface of the out-coupling region 10b of the waveguide substrate 10 can include a convex surface 10a and a concave surface 10b arranged oppositely, and the distance between the convex surface 10a and the concave surface 10b can be equal.
[0046] For example, as shown in FIG. 7, the curved surface of the out-coupling region 10b of the waveguide substrate 10 can include a convex surface 10a and a concave surface 10b arranged oppositely, and the distance between the convex surface 10a and the concave surface 10b can be equal.
[0047] For example, the out-coupling grating 30 can be a transmissive grating or a reflective grating, which can be adjusted according to actual conditions and is not limited herein. The in-coupling grating 20 and the out-coupling grating 30 can be arranged on the same side of the waveguide substrate 10, or the in-coupling grating 20 and the out-coupling grating 30 can be arranged on opposite sides of the waveguide substrate 10.
[0048] In some embodiments, the out-coupling gratings 30 are surface relief gratings, or the out-coupling gratings 30 are volume holographic gratings. It can be understood that the out-coupling gratings 30 are arranged flexibly and freely, and the surface relief gratings or the volume holographic gratings can be selected as the out-coupling gratings 30 according to actual needs, and by adjusting the parameters of the surface relief gratings or the volume holographic gratings, the structures of the plurality of out-coupling gratings 30 can be different, so that the plurality of out-coupling gratings 30 have different diffraction effects.
[0049] In some embodiments, the plurality of out-coupling gratings 30 are arranged at intervals. Alternatively, the plurality of out-coupling gratings 30 are arranged in close contact. It can be understood that the positional relationship between the two adjacent out-coupling gratings 30 is flexible and free, and can be adjusted according to actual conditions. For example, the plurality of out-coupling gratings 30 are arranged at intervals, and the distance between the two adjacent out-coupling gratings 30 can be adjusted according to actual conditions, so as to facilitate the processing and preparation of the plurality of out-coupling gratings 30 while achieving high-efficiency light coupling.
[0050] In some embodiments, the plurality of out-coupling gratings 30 are arranged uniformly, and the distance between the plurality of out-coupling gratings 30 is uniform, which is beneficial to uniformly diffract light at different positions, improve the imaging clarity, and facilitate the determination of the structure of the plurality of out-coupling gratings 30.
[0051] In some embodiments, the light coupled out by the plurality of out-coupling gratings 30 converges. Alternatively, the light coupled out by the plurality of out-coupling gratings 30 diverges. Alternatively, the transmission directions of the light coupled out by at least two out-coupling gratings 30 are different. Alternatively, the transmission directions of the light coupled out by at least two out-coupling gratings 30 are the same. It can be understood that the transmission direction of the light coupled out by the out-coupling gratings 30 is flexible and can be adjusted according to actual needs to adapt to different user groups.
[0052] For example, when the optical waveguide 100 is applied to a near-eye display device, if the optical waveguide 100 is located in a range that is difficult for a user to see, the light rays with the same field of view can converge to a point through the extension lines of the light rays coupled out by the plurality of out-coupling gratings 30, or the light rays with the same field of view can gradually disperse between the extension lines of the light rays coupled out by the plurality of out-coupling gratings 30, so that the out-coupling gratings 30 can clearly image in the human eye after entering the human eye.
[0053] For example, when the optical waveguide 100 is applied to a near-eye display device, if the distance between the optical waveguide 100 and the human eye is close, when the optical waveguide 100 is located in a range that can be seen by a user, the transmission directions of the light rays with the same field of view after being coupled out by the plurality of out-coupling gratings 30 are the same, and the light rays are transmitted to the human eye with the same transmission direction.
[0054] For example, as shown in FIG. 1, the plurality of out-coupling gratings 30 are arranged at intervals, and the distance between the two adjacent out-coupling gratings 30 is adjustable. Figure 2As shown, the in-coupling region 10a and the out-coupling region 10b of the waveguide substrate 10 both have curved surfaces, the near-eye display device includes a light engine 200, a lens module and a light waveguide 100, the virtual image light beam emitted by the light engine 200 includes light rays of different field angles, the virtual image light beam is transmitted to the in-coupling grating 20 after being collimated and aberration-corrected by the lens module, and is coupled into the waveguide substrate 10 through the in-coupling grating 20, the light beam is transmitted to the out-coupling region 10b, and the light rays of the same field angle are coupled out through the plurality of out-coupling gratings 30 on the curved surface and can be transmitted to the human eye in the same direction.
[0055] In some embodiments, the grating periods of the plurality of out-coupling gratings 30 are different, so that the plurality of out-coupling gratings 30 have different diffraction effects.
[0056] For example, when the out-coupling grating 30 is a volume holographic grating, the volume holographic grating has bright and dark stripes, and the transverse period can be understood as the projection of the distance between the center lines of two adjacent dark stripes in the x-y plane, for example, the projection of the distance between the center lines of two adjacent dark stripes in the tangent plane of the out-coupling grating 30.
[0057] For example, as shown in FIG. 3, the out-coupling grating 30 has a transverse period P1 and a transverse period P2, and the transverse period P1 is different from the transverse period P2. Figure 2 As shown, the in-coupling region 10a and the out-coupling region 10b of the waveguide substrate 10 both have curved surfaces, the near-eye display device includes a light engine 200, a lens module and a light waveguide 100, the virtual image light beam emitted by the light engine 200 includes light rays of different field angles, the virtual image light beam is transmitted to the in-coupling grating 20 after being collimated and aberration-corrected by the lens module 300, and is coupled into the waveguide substrate 10 through the in-coupling grating 20, the light beam is transmitted to the out-coupling region 10b, and the grating periods of the plurality of out-coupling gratings 30 on the curved surface of the out-coupling region 10b vary, for example, the transverse periods vary, so that when the light rays of the same field angle coupled into the waveguide substrate 10 are coupled out of the waveguide substrate 10 by the plurality of out-coupling gratings 30, the light rays are still transmitted in the same direction.
[0058] In some embodiments, the projection of the grating period of the out-coupling grating 30 on the plane where the in-coupling grating 20 is located is equal to the grating period of the in-coupling grating 20, which satisfies the k-vector closure principle, avoids the image formed by the coupled-out light rays from having ghosting, and improves the imaging quality.
[0059] It is worth noting that the plane where the in-coupling grating 20 is located can be the actual waveguide substrate 10 on the waveguide substrate 10, or can be the tangent plane of the waveguide substrate 10 at the in-coupling grating 20.
[0060] For example, as shown in FIG. 3, the transverse period of the out-coupling grating 30 in the plane where the in-coupling grating 20 is located is equal to the transverse period of the in-coupling grating 20. Figure 4As shown, the in-coupling grating 20 and the in-coupling grating 20 are both arranged on a concave surface, and the plane where the in-coupling grating 20 is arranged can be as shown in the plane S1 perpendicular to the paper Figure 4 As shown in the plane S1 perpendicular to the paper, the area of the out-coupling grating 30 is relatively small, and it is approximately determined that the out-coupling grating 30 is arranged obliquely, and the angle between the tangent plane of the waveguide substrate 10 at the out-coupling grating 30 and the tangent plane of the waveguide substrate 10 at the in-coupling grating 20 is θ, then the transverse period kx of the in-coupling grating 20 and the transverse period kx1 of the out-coupling grating 30 satisfy the relationship: kx1=kx / cosθ.
[0061] The embodiment of the present application also provides a near-eye display device, which comprises the optical waveguide 100 as described above. It can be understood that the near-eye display device with the optical waveguide 100 as described above has all the technical effects, that is, the refractive adjustment can be realized, so that the external environment light and the virtual image light can be clearly imaged in the human eye, and it is not necessary to additionally increase a lens group or an optical adjustment element in the near-eye display device, which is beneficial to reducing the weight and the volume of the near-eye display device.
[0062] For example, the near-eye display device can be an augmented reality display device, a virtual reality display device, etc.
[0063] It should be understood that the term "and / or" used in the present application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. It should be noted that in this document, the term "comprise", "include" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed or inherent to such a process, method, article or system. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article or system including the element.
[0064] The above-mentioned serial numbers of the embodiments of the present application are only for description, and do not represent the advantages and disadvantages of the embodiments. The above description is only for specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical range disclosed in the present application, and these modifications or replacements should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.
Claims
1. An optical waveguide, characterized by, The application relates to an optical waveguide, comprising: a waveguide substrate, the waveguide substrate having curved surfaces on opposite sides; an in-coupling grating arranged on the waveguide substrate, the in-coupling grating being configured to in-couple light into the waveguide substrate so that the light propagates in the waveguide substrate; and a plurality of out-coupling gratings arranged on the curved surfaces or on the surfaces of the waveguide substrate opposite to the curved surfaces, the out-coupling gratings being configured to out-couple the light propagating in the waveguide substrate from the waveguide substrate, and the out-coupling gratings having different structures.
2. The optical waveguide of claim 1, wherein, The grating periods of the out-coupling gratings are different.
3. The optical waveguide of claim 2, wherein, The grating period of the out-coupling gratings in the projection of the plane in which the in-coupling grating is located is equal to the grating period of the in-coupling grating.
4. The optical waveguide according to any one of claims 1 to 3, wherein The out-coupling gratings are arranged in intervals or are arranged in close contact.
5. The optical waveguide of any of claims 1-3, wherein, The light out-coupled by the out-coupling gratings converges; or The light out-coupled by the out-coupling gratings diverges. Or The transmission directions of the light out-coupled by at least two out-coupling gratings are different. The transmission directions of the light out-coupled by at least two out-coupling gratings are the same.
6. The optical waveguide of any of claims 1-3, wherein, The out-coupling gratings are surface relief gratings or volume holographic gratings.
7. The optical waveguide of any of claims 1-3, wherein, The out-coupling gratings are uniformly arranged.
8. The optical waveguide of any of claims 1-3, wherein, The curved surfaces comprise convex surfaces, and the out-coupling gratings are arranged on the convex surfaces.
9. The optical waveguide of any of claims 1-3, wherein, The curved surfaces comprise opposite convex surfaces and concave surfaces, and the distances between the convex surfaces and the concave surfaces are equal.
10. A near-eye display device, comprising: The application further relates to an optical waveguide comprising any one of the above-mentioned optical waveguidages.