Light waveguide and display device

Abstract

Embodiments of the present disclosure provide a light waveguide and a display device. The light waveguide includes a substrate, a coupling-in element, and a coupling-out element. The coupling-in element is on the substrate and configured to couple light of different incident angles into the substrate. The coupling-out element is on the substrate and includes a first region, a second region, and a third region sequentially arranged along a propagation direction of the light. The first region selectively couples out light within a first incident angle range and restricts coupling out of light within a second incident angle range. The second region couples out light within both the first incident angle range and the second incident angle range. The third region selectively couples out light within the second incident angle range and restricts coupling out of light within the first incident angle range. The first incident angle range and the second incident angle range partially overlap.

Description

Technical Field

[0001] This application relates to the field of optical waveguide technology, and more specifically, to an optical waveguide and display device. Prior Technology

[0002] Augmented Reality (AR) technology merges the virtual and real worlds, allowing users to interact with digital content more naturally. For AR-enabled display devices, factors such as the field of view (FOV), eyebox size, image continuity, and color uniformity all affect the user experience.

[0003] For display devices that combine diffraction waveguide technology and AR technology, conventional ways to increase their field of view either increase the thickness of the diffraction waveguide or reduce the light utilization of the AR device. Summary of the Invention

[0004] Therefore, it is necessary to provide an optical waveguide and display device to improve the eye box of a display device combining diffraction waveguide technology and AR technology while avoiding increasing the thickness of the optical waveguide and reducing the light utilization rate.

[0005] This application provides an optical waveguide. The optical waveguide includes a substrate, a coupling element, and a coupling element. The coupling element is disposed on the substrate for coupling light at different incident angles into the substrate. The coupling element is disposed on the substrate. The coupling element has a plurality of coupling regions. The plurality of coupling regions are configured to selectively couple light out according to the incident angle. The plurality of coupling regions includes a first region, a second region, and a third region arranged sequentially along the light propagation direction. The first region is configured to selectively couple light out within a first incident angle range and restrict the coupling out of light within a second incident angle range. The second region is configured to couple light out within both the first and second incident angle ranges. The third region is configured to selectively couple light out within the second incident angle range and restrict the coupling out of light within the first incident angle range. The first and second incident angle ranges partially overlap.

[0006] The optical waveguide in this embodiment of the application can effectively expand the eye box by selectively coupling out light at different angles from different regions. Compared with single-angle coupling, multi-angle multiplexing can cover a wider angle range.

[0007] Furthermore, conventional multi-angle multiplexing uses the same multiplexing method throughout the entire output area, resulting in some light being coupled out in unsuitable areas and failing to enter the human eye, causing waste. The optical waveguide of this application embodiment, by partitioning the output elements, controls the coupling of light at specific angles to specific areas. Compared with conventional multi-angle multiplexing, the optical waveguide of this application embodiment can avoid unnecessary light coupling out, reduce light waste, thereby improving light utilization and thus improving the overall screen brightness of the display device using the optical waveguide.

[0008] Furthermore, the optical waveguide in this application embodiment achieves the expansion of the eye box and the improvement of light utilization by optimizing the structural design of the coupling region, without increasing the number of waveguide layers, and therefore does not increase the thickness of the optical waveguide.

[0009] A second aspect of this application provides a display device. The display device includes an optomechanical system and an optical waveguide as provided in the first aspect of this application. The optical waveguide is used to receive light projected by the optomechanical system.

[0010] The display device of the second aspect of this application has at least the same advantages as the optical waveguide of the first aspect of this application, which will not be repeated here. Simple Explanation of the Diagram

[0011] Figure 1(a) and (b) are schematic diagrams of the structure of monolithic and multi-chip optical waveguides in related technologies, respectively.

[0012] Figures (a), (b), and (c) in Figure 2 are schematic diagrams of the structure, shooting architecture, and FOV of a single-angle VHOE in the related technology, respectively; Figures (d), (e), and (f) in Figure 2 are schematic diagrams of the structure, shooting architecture, and FOV of a dual-angle VHOE in the related technology, respectively.

[0013] Figures (a), (b), and (c) in Figure 3 are schematic diagrams of light propagation at different incident angles in a display device with a multi-angle VHOE optical waveguide in the related art.

[0014] Figures (a), (b), and (c) in Figure 4 are schematic diagrams of light propagation at different incident angles in a display device according to an embodiment of this application.

[0015] Figures (a), (b), and (c) in Figure 5 are schematic diagrams of the incident angle, spectral flux, and reconstructed wavelength of the first, second, and third regions in an optical waveguide according to an embodiment of this application.

[0016] Figures (a) and (b) in Figure 6 are schematic diagrams showing the eyebox size of optical waveguides in related technologies and optical waveguides in an embodiment of this application, respectively. Implementation

[0017] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the embodiments of this application, and should not be construed as limiting this application.

[0018] In the description of the embodiments of this application, the terms "thickness", "upper", "lower", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the implementation of this application and simplifying the 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. Therefore, they should not be construed as limitations on this application.

[0019] In the description of the embodiments of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features.

[0020] In the description of the embodiments of this application, unless otherwise stated, "plural" means two or more.

[0021] In the description of the embodiments of this application, unless otherwise stated, the term "connection" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction between two elements.

[0022] Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0023] Figures (a) and (b) in Figure 1 are schematic diagrams of monolithic and multi-layer optical waveguides in related technologies, respectively. As shown in Figure 1(a), optical waveguide 1 is a monolithic optical waveguide. Red light R, green light G, and blue light B enter the human eye E after passing through optical waveguide 1. Since optical waveguide 1 is a monolithic optical waveguide, or a single-layer optical waveguide, its entire eye box is non-uniform, and the field of view (FOV) of optical waveguide 1 is very small. To improve the FOV of optical waveguide 1, one approach is to use a multi-layer optical waveguide as shown in Figure 1(b), that is, to use two or even three waveguides stacked together.

[0024] As shown in Figure 1(b), the optical waveguide 2 is composed of three stacked optical waveguides. Red light R, green light G, and blue light B are transmitted through one of the optical waveguides in optical waveguide 2 and finally enter the human eye E. As can be seen from Figures 1(a) and (b), although this method can improve the FOV of the optical waveguide, the thickness of optical waveguide 2 increases, which prevents the thickness of the display device (such as AR glasses) using this optical waveguide 2 from being reduced.

[0025] Figures 2(a), 2(b), and 2(c) show the structural diagram, shooting architecture diagram, and FOV diagram of a single-angle volume holographic optical element (VHOE) in the related technology, respectively. As shown in Figures 2(a), 2(b), and 2(c), the single-angle VHOE3 is formed by single-angle exposure. The single-angle exposure method uses two beams of light (i.e., reference light Lr and signal light Ls) to interfere. However, because VHOE has high selectivity for angles, the FOV of the single-angle VHOE3 obtained when shooting from a single angle is very small (assuming it is 9°).

[0026] Figures (d), (e), and (f) in Figure 2 are schematic diagrams of the structure, shooting architecture, and FOV of a dual-angle VHOE, respectively. As shown in Figures (d), (e), and (f) in Figure 2, another method is to improve the FOV through multi-angle multiplexing (also known as multi-angle multiplexing). The dual-angle VHOE4 in Figure 2 is formed by dual-angle exposure. Dual-angle multiplexing exposure involves interfering four beams (reference light Lr1, reference light Lr2, signal light Ls1, and signal light Ls2) in pairs, which can increase the FOV to ±10°.

[0027] Figures (a), (b), and (c) in Figure 3 are schematic diagrams of light propagation at different incident angles in a display device with a multi-angle VHOE optical waveguide in the related art.

[0028] In Figure 3, the display device 100' includes an optomechanical system 10' and an optical waveguide 20'. The optical waveguide 20' is located on the light-emitting side of the optomechanical system 10'. The optomechanical system 10' is used to project image light onto the optical waveguide 20'.

[0029] The optical waveguide 20' includes a substrate 21', a coupling element 22', and a coupling element 23'. Both the coupling element 22' and the coupling element 23' are disposed on the substrate 21' and are gratings. The coupling element 23' is a multi-angle VHOE, employing multi-angle multiplexing, a common practice where the entire coupling region uses the same multiplexing method. When light travels through the optical waveguide 20' to the coupling region, light from various angles will be coupled out by the coupling element 23', but some angles of light will not effectively enter the human eye.

[0030] Specifically, Figures (a), (b), and (c) in Figure 3 represent the paths of light at different incident angles within the optical waveguide 20'.

[0031] As shown in Figures (a), (b), and (c) of Figure 3, light from different incident angles at the same position of the coupling element 23' (such as light L1 within the first incident angle range, light L2 within the second incident angle range, and light L3 within the third incident angle range) will all be emitted. However, some of the light coupled out from the coupling element 23' does not enter the human eye, and that light is wasted. If the eye position is moved, although the image can be seen, both IMG2 and IMG3 are incomplete, so they are not considered within the range of the eye box EB. The eye box is defined as the range within which a complete image (such as image IMG1) can be seen.

[0032] Figures (a), (b), and (c) in Figure 4 are schematic diagrams illustrating the propagation of light at different incident angles in a display device according to an embodiment of this application. As shown in Figure 4, the display device 100 includes an optomechanical system 10 and an optical waveguide 20. The optical waveguide 20 is located on the light-emitting side of the optomechanical system 10. The optical waveguide 20 is used to receive light projected by the optomechanical system 10.

[0033] In some embodiments, the optomechanical system 10 can be, but is not limited to, any one of an organic light-emitting diode display, a micro inorganic light-emitting diode display, a liquid crystal display, a silicon-based liquid crystal display, a digital micromirror device, and a laser beam scanner.

[0034] Specifically, the optical waveguide 20 includes a substrate 21, a coupling element 22, and a coupling element 23. The coupling element 22 is disposed on the substrate 21 and is used to couple light into the substrate 21 at different incident angles. The coupling element 23 is disposed on the substrate 21. The coupling element 23 has a plurality of coupling regions A. The plurality of coupling regions A are configured to selectively couple light out according to the incident angle.

[0035] The complex coupling region A includes a first region A1, a second region A2, and a third region A3 arranged sequentially along the direction of light propagation.

[0036] The first region A1 is configured to selectively couple out light L1 within a first incident angle range and restrict the coupling out of light L2 within a second incident angle range.

[0037] The second region A2 is configured to couple out light L1 within a first incident angle range and light L2 within a second incident angle range.

[0038] The third region A3 is configured to selectively couple out light L2 within the second incident angle range and restrict the coupling out of light L1 within the first incident angle range. The first and second incident angle ranges partially overlap.

[0039] The optical waveguide 20 of this application embodiment can effectively expand the eye box by selectively coupling light at different angles through different coupling regions A. Compared with single-angle coupling, multi-angle multiplexing can cover a wider angle range.

[0040] Furthermore, conventional multi-angle multiplexing uses the same multiplexing method throughout the entire output region, resulting in some light being coupled out in unsuitable areas and failing to enter the human eye, thus causing waste. The optical waveguide 20 of this application embodiment, by partitioning the output element 23, controls the coupling of light at specific angles to specific areas. Compared to conventional multi-angle multiplexing, the optical waveguide 20 of this application embodiment can avoid unnecessary light coupling out, reduce light waste, and thereby improve light utilization.

[0041] Furthermore, the optical waveguide 20 in this embodiment achieves the expansion of the eye box and the improvement of light utilization by optimizing the structural design of the coupling region, without increasing the number of waveguide layers, and therefore does not increase the thickness of the optical waveguide 20.

[0042] In some embodiments, the third region A3 is further configured to selectively couple light L3 within a third incident angle range, which partially overlaps with the second incident angle range. This allows for further expansion of the eye box and improved light utilization by quoting light L3 within the third incident angle range from the third region A3.

[0043] Specifically, Figures (a), (b), and (c) in Figure 4 are schematic diagrams of the optical paths after light L1 within the first incident angle range, light L2 within the second incident angle range, and light L3 within the third incident angle range are incident into the optical waveguide 20.

[0044] As shown in Figures (a), (b) and (c) of Figure 4, at the first region A1, light L1 within the first incident angle range is coupled out, while light L2 within the second incident angle range and light L3 within the third incident angle range are restricted from coupling out or are not coupled out.

[0045] At the second region A2, light L1 within the first incident angle range and light L2 within the second incident angle range are both coupled out, while light L3 within the third incident angle range is restricted from being coupled out or is not coupled out.

[0046] At the third region A3, light L2 within the second incident angle range and light L3 within the third incident angle range are both coupled out, while light L1 within the first incident angle range has been almost entirely coupled out in the first region A1 and the second region A2. Therefore, light L1 within the first incident angle range will not be transmitted to the third region A3, thus avoiding waste.

[0047] In some embodiments, the partitioning of the coupling element 23 is not only designed for the incident angle, but also allows for different efficiencies in each coupling region A. The aim is to ensure that light is almost completely coupled out at a specific location, without wasting light by continuing to propagate backward.

[0048] In some embodiments, the coupling element 23 is a volume holographic grating, the first region A1 includes at least one set of grating arrays, the second region A2 includes at least two sets of grating arrays, and the third region A3 includes at least one set of grating arrays. Each grating array includes at least two grating stripes. Different sets of grating arrays in each coupling region A have different angle selectivity to diffract light from different incident angle ranges.

[0049] Therefore, the coupling element 23 in this embodiment employs a volume holographic grating, utilizing its diffraction characteristics to achieve selective coupling of light. The angular selectivity of each region is controlled by the number of grating arrays, resulting in a simple structure that is easy to implement.

[0050] Figures (a), (b), and (c) in Figure 5 are schematic diagrams showing the incident angle, spectral flux, and reconstructed wavelength of the first, second, and third regions in an optical waveguide according to an embodiment of this application. Specifically, in the schematic diagrams of incident angle, spectral flux, and reconstructed wavelength, the horizontal axis represents the reconstructed wavelength, and the vertical axes represent the incident angle and spectral flux, respectively. The grayscale distribution represents the magnitude of the spectral flux, or diffraction efficiency. The brighter the grayscale, the higher the diffraction efficiency.

[0051] As shown in Figure 5(a), corresponding to the first region, a set of grating arrays is used to couple out light in the first incident angle range (such as light with an efficiency greater than 0.8 in the incident angle range of approximately -10° to 0°).

[0052] As shown in Figure 5(b), corresponding to the second region, two sets of grating arrays are used to couple out light in the first incident angle range (such as light with an incident angle range of approximately -10° to 0° with an efficiency greater than 0.8) and light in the second incident angle range (such as light with an incident angle range of approximately -5° to 4° with an efficiency greater than 0.8).

[0053] As shown in Figure 5(c), corresponding to the third region, two sets of grating arrays are used to couple out light from the second incident angle range (such as light with an incident angle range of approximately -5° to 4° with an efficiency greater than 0.8) and light from the third incident angle range (such as light with an incident angle range of approximately 2° to 10° with an efficiency greater than 0.8).

[0054] In some embodiments, the number of grating arrays in each coupling region A is no more than 10 groups (e.g., 1 group, 2 groups, 3 groups, 4 groups, 5 groups, 6 groups, 7 groups, 8 groups, 9 groups, 10 groups, etc.). In this way, by limiting the number of grating arrays in each coupling region, the efficiency dispersion caused by an excessive number of gratings is avoided, and the diffraction efficiency of the coupling element is guaranteed.

[0055] In some embodiments, the spacing between two adjacent grating stripes ranges from 0.1 micrometers to 10 micrometers (e.g., 0.1 micrometers to 0.5 micrometers, 0.5 micrometers to 1 micrometer, 1 micrometer to 5 micrometers, 5 micrometers to 8 micrometers, 8 micrometers to 10 micrometers, etc.). This ensures the diffraction effect of the grating by limiting the range of grating stripe spacing.

[0056] In some embodiments, the coupling element 23 includes a photosensitive material layer, which includes, but is not limited to, one of silver halide, optical crystal, and photosensitive polymer. Therefore, by using the aforementioned materials to write the photosensitive material layer into the grating during the exposure recording process, it is beneficial to ensure the recording quality of the grating.

[0057] In other embodiments, the coupling element 23 may also employ different grating structures, such as blazed gratings, to achieve adjustment of diffraction efficiency and angle selectivity.

[0058] In some embodiments, the refractive index of the substrate 21 is in the range of 1.3 to 2.5 (e.g., 1.3 to 1.5, 1.5 to 1.8, 1.8 to 2.0, 2.0 to 2.3, 2.3 to 2.5, etc.). Therefore, limiting the refractive index of the substrate 21 to the above range is beneficial for ensuring total internal reflection of light within the substrate 21 of the optical waveguide 20.

[0059] In some embodiments, the material of the substrate 21 may be, but is not limited to, glass or polymethyl methacrylate (PMMA).

[0060] In some embodiments, light at different incident angles has a single wavelength. For example, the single wavelength can be, but is not limited to, red, green, or blue light.

[0061] In some embodiments, the light at different incident angles contains at least two different wavelengths. For example, the at least two different wavelengths can be a combination of red and green light; or a combination of red and blue light; or a combination of blue and green light; or a combination of red, green, and blue light. Therefore, by having the light at different incident angles contain at least two different wavelengths, it is advantageous for the display device utilizing this optical waveguide to achieve better color display effects.

[0062] In other embodiments, the number of coupling regions A can be varied. For example, there may be two coupling regions A; or there may be four or more coupling regions A to achieve a wider eye box.

[0063] In this embodiment of the optical waveguide 20, the coupling element 23 is designed as a plurality of coupling regions A, each coupling region A having a different angle (multiplexing) design, which also helps to increase the size of the eye box. The following description is in conjunction with FIG6.

[0064] Figures (a) and (b) in Figure 6 are schematic diagrams of the eyebox size of optical waveguides in the related art and an embodiment of the present application, respectively. As shown in Figure (a) in Figure 6, in the optical waveguide 20' of the related art, since there is no partition design for the coupling element 23', the efficiency of each position of the coupling element 23' is the same.

[0065] Figure 6(a) shows, from top to bottom, the energy distribution of light L1 within the first incident angle range after being coupled out by the coupling element 23', the energy distribution of light L2 within the second incident angle range after being coupled out by the coupling element 23', and the energy distribution of light L1 within the first incident angle range and light L2 within the second incident angle range after being coupled out by the coupling element 23' and superimposed.

[0066] Specifically, along the direction of light propagation (i.e., in the direction indicated by the arrow at coupling element 23'), the energy of light L1 within the first incident angle range gradually decreases. In Figure 6(a), along the direction of light propagation, each rhombus represents the energy of light L1 within the first incident angle range gradually being halved, and the energies of the light represented by the four rhombuses are approximately 50%, 25%, 12.5%, and 6.25% respectively.

[0067] Similarly, in Figure 6(b), along the direction of light propagation, each rhombus indicates that the energy of light L2 within the second incident angle range is gradually halved, and the energy of the light indicated by the four rhombuses is approximately 50%, 25%, 12.5%, and 6.25% respectively.

[0068] Therefore, in Figure 6(a), after the light L1 in the first incident angle range and the light L2 in the second incident angle range coupled from the coupling element 23' are superimposed, some of the energy is too low (e.g., less than 10%), resulting in unclear images. This makes the actual size of the eye box EB smaller than the ideal size of the eye box EB'.

[0069] However, as shown in Figure 6(b), in the optical waveguide 20 of this embodiment, since multiple coupling regions A are designed for the coupling element 23, the coupling efficiency of different coupling regions A varies for light with different incident angles. Specifically, the first region A1 will not allow light L2 within the second incident angle range to be coupled out, and the third region A3 will not allow light L1 within the first incident angle range to be coupled out. Furthermore, with different efficiency controls, the energy of light L1 within the first incident angle range coupled out from the first region A1 and the two second regions A2 is roughly equivalent (e.g., approximately 31.25%); the energy of light L1 within the first incident angle range coupled out from the two second regions A2 and the third region A3 is also roughly equivalent (e.g., approximately 31.25%).

[0070] In this way, the light L1 within the first incident angle range and the light L2 within the second incident angle range coupled from the coupling element 23 are superimposed, making the actual size of the eye box EB consistent with the size of the ideal eye box EB'. Therefore, the optical waveguide 20 of this embodiment facilitates the expansion of the eye box size, achieving a larger eye box.

[0071] In some embodiments, the display device 100 is a near-eye display device. The near-eye display device may be configured in the form of glasses (such as AR glasses), or in the form of a helmet or goggles, and there is no limitation thereto.

[0072] Specifically, the AR glasses (not shown) may include an eyeglass frame and temples attached to both sides of the frame. The optical engine 10 may be mounted on the eyeglass frame or on the temples on both sides. Optical waveguides 20 are mounted on the eyeglass frame and are respectively positioned for the user's eyes.

[0073] In some embodiments, the display device 100 is an in-vehicle display. The vehicle includes a windshield, and the optical waveguide 20 may be disposed inside or on the inner side of the windshield to project the light projected by the optical engine 10 onto the windshield.

[0074] Understandably, the display device 100 can also be applied to other scenarios that enhance display, and is not limited to those described above.

[0075] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of this application should not depart from the spirit and scope of the technical solutions of this application.

[0076] 100, 100': Display device

[0077] 10, 10': Optical engine

[0078] 20, 20', 1, 2: Optical waveguide

[0079] 21, 21': Base

[0080] 22, 22': Coupled elements

[0081] 23, 23': Coupling elements

[0082] A: Coupling region

[0083] A1: First Area

[0084] A2: Second Area

[0085] A3: Third Area

[0086] L1: Light within the first incident angle range

[0087] L2: Light within the second incident angle range

[0088] L3: Light within the third incident angle range

[0089] B: Blue light

[0090] G: Green Light

[0091] R: Red light

[0092] E: Eyes

[0093] EB, EB': Eye Box

[0094] 3: Single-angle VHOE

[0095] 4: Dual-angle VHOE

[0096] Lr, Lr1, Lr2: Reference light

[0097] Ls, Ls1, Ls2: Signal light

[0098] IMG1, IMG2, IMG3: Images

Claims

1. An optical waveguide, comprising: Base; A coupling element, disposed on the substrate, is used to couple light at different incident angles into the substrate; The system includes a coupling element disposed on the substrate. The coupling element has multiple coupling regions configured to selectively couple light according to the incident angle. The multiple coupling regions include a first region, a second region, and a third region arranged sequentially along the light propagation direction. The first region is configured to selectively couple light within a first incident angle range and restrict the coupling of light within a second incident angle range. The second region is configured to couple light within both the first and second incident angle ranges. The grating structure of the third region is configured to selectively couple light within the second incident angle range and restrict the coupling of light within the first incident angle range. The first and second incident angle ranges partially overlap. The coupling element is a volume holographic grating. The first region includes at least one set of grating arrays, the second region includes at least two sets of grating arrays, and the third region includes at least one set of grating arrays. Each grating array includes at least two grating stripes. Different sets of grating arrays in the second region have different angular selectivity for diffracting and coupling light from different incident angle ranges.

2. The optical waveguide as described in claim 1, wherein, In each of the coupling regions, the number of grating arrays is no more than 10 groups.

3. The optical waveguide as described in claim 1, wherein, The spacing between two adjacent grating stripes ranges from 0.1 micrometers to 10 micrometers.

4. The optical waveguide as described in claim 1, wherein, The coupling element includes a photosensitive material layer, which includes one of silver halide, optical crystal, and photosensitive polymer material.

5. The optical waveguide as described in any one of claims 1 to 4, wherein, The refractive index of the substrate ranges from 1.3 to 2.

5.

6. The optical waveguide as described in any one of claims 1 to 4, wherein, The light at different incident angles has a single wavelength; or, the light at different incident angles contains at least two different wavelengths.

7. The optical waveguide as described in any one of claims 1 to 4, wherein, The third region is also configured to selectively couple light out within a third incident angle range, which partially overlaps with the second incident angle range.

8. A display device, comprising: Optical mechanism; And an optical waveguide as described in any one of claims 1 to 7, the optical waveguide being used to receive light projected by the optomechanism.

9. The display device as claimed in claim 8, wherein, The display device is a near-eye display device; or, the display device is a vehicle-mounted display.

Images