Optical waveguide structure and display device

Abstract

The invention provides an optical waveguide structure. The optical waveguide structure comprises an optical waveguide, a coupling-in grating and a coupling-out grating, wherein the coupling-in grating and the coupling-out grating are located on the same surface of the optical waveguide and are arranged at intervals; the optical waveguide comprises a first light guide part and a second light guide part which are spliced with each other, the refractive index of the first light guide part is smaller than that of the second light guide part, and orthographic projections of the coupling-in grating and the coupling-out grating on the optical waveguide in the thickness direction of the optical waveguide are located on the first light guide part; and the coupling-in grating is used for coupling image light into the optical waveguide, so that the image light is coupled out of the optical waveguide from the coupling-out grating after sequentially passing through the first light guide part, the second light guide part and the first light guide part. The invention further provides a display device.

Description

Technical Field

[0001] The present application relates to an optical waveguide structure and a display device including the optical waveguide structure. Background Art

[0002] For a display device using Augmented Reality (AR) technology (hereinafter referred to as an AR display device), by combining virtual images with a real scene, users can naturally interact with digital content, which has become an industrial development goal. AR display devices include AR near-eye display devices and AR head-up display devices. Optical waveguides have gradually been regarded as the mainstream solution to meet the imaging requirements of AR display devices. This is mainly because optical waveguides can achieve total internal reflection of light. That is, after an optical engine completes imaging (generating image light), the image light is coupled into the optical waveguide, and the optical waveguide transmits the image light to the front of the eyes (for near-eye display devices) or the windshield (for head-up display devices) through the "total internal reflection" principle, and then releases it and is received by the human eye for imaging.

[0003] Currently, in an AR display device, during the process of the image light conducting from the coupling grating to the output grating in the optical waveguide, part of the image light gradually shifts towards the edge of the optical waveguide, resulting in difficulty for this part of the image light to exit from the area corresponding to the eye box on the output grating, reducing the amount of image light received by the human eye and making the brightness of the display image seen by the user dim. Summary of the Invention

[0004] A first aspect of the present application provides an optical waveguide structure, including:

[0005] An optical waveguide and a coupling grating and an output grating which are located on the same surface of the optical waveguide and are spaced apart;

[0006] The optical waveguide includes a first light guiding portion and a second light guiding portion spliced together, the refractive index of the first light guiding portion is less than that of the second light guiding portion, and the orthographic projections of the coupling grating and the output grating on the optical waveguide in the thickness direction of the optical waveguide are located on the first light guiding portion;

[0007] The coupling grating is used to couple image light into the optical waveguide, so that the image light sequentially passes through the first light guiding portion, the second light guiding portion, and the first light guiding portion and then is coupled out of the optical waveguide from the output grating.

[0008] In the optical waveguide structure provided by the embodiments of the present application, when image light is coupled into the first light guiding portion through the coupling grating and propagates in the first light guiding portion, part of the image light will deviate from the preset propagation direction and shift towards the two side edges close to the optical waveguide. Since the refractive index of the first light guiding portion is less than that of the second light guiding portion, after the image light is refracted and transmitted by the second light guiding portion, the deviation degree of the image light towards the edge of the optical waveguide is corrected, reducing the deviation degree, so that the quantity of the image light coupled out from the coupling grating and received by the human eye increases, thereby improving the brightness of the display image seen by the human eye.

[0009] The second aspect of the present application provides a display device, including:

[0010] A display for emitting image light;

[0011] The optical waveguide structure as described above, wherein the coupling grating of the optical waveguide structure is located on the optical path of the image light and is used for coupling the image light into the optical waveguide.

[0012] For the above display device, the above optical waveguide structure is integrated, and all the beneficial effects of the above optical waveguide structure can be achieved. Description of the Drawings

[0013] Figure 1 It is a schematic plan view of the optical waveguide structure of the related art.

[0014] Figure 2 It is a schematic three-dimensional view of the optical waveguide structure of the first embodiment of the present application.

[0015] Figure 3 For Figure 2 the schematic plan view of the optical waveguide structure in

[0016] Figure 4 It is a schematic plan view of the optical waveguide structure when the coupling grating and the output grating are arranged on different surfaces of the optical waveguide.

[0017] Figure 5 For the Figure 2 optical path schematic diagram when the image light propagates in the optical waveguide structure of

[0018] Figure 6 It is a schematic plan view of the optical waveguide structure of the second embodiment of the present application.

[0019] Figure 7 For the Figure 6 optical path schematic diagram when the image light propagates in the optical waveguide structure of

[0020] Figure 8 It is a schematic plan view of the optical waveguide structure of the third embodiment of the present application.

[0021] Figure 9 Schematic plan view of the optical waveguide structure according to the fourth embodiment of the present application.

[0022] Figure 10 Schematic three-dimensional view of the AR near-eye display device according to the embodiment of the present application.

[0023] Figure 11 is Figure 10 Schematic optical path diagram of the image light emitted by the display in the AR near-eye display device.

[0024] Figure 12 Schematic optical path diagram of the image light in the AR head-up display device according to the embodiment of the present application.

[0025] Description of main component symbols:

[0026] AR near-eye display device 100

[0027] AR head-up display device 200

[0028] Optical waveguide structures 1a, 1

[0029] Optical waveguides 10a, 10

[0030] First surface 101

[0031] Second surface 102

[0032] First light guiding portion 11

[0033] First part 111

[0034] Second part 112

[0035] Second light guiding portion 12

[0036] First side surface 121

[0037] Second side surface 122

[0038] Third side surface 123

[0039] Fourth side surface 124

[0040] Coupling-in gratings 20a, 20

[0041] Coupling-out gratings 30a, 30

[0042] Receiving regions 31a, 31

[0043] Display 2

[0044] Collimating lens 3

[0045] Imaging medium 4

[0046] Image light LSa, LS

[0047] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific embodiments

[0048] Figure 1 It is a schematic plan view of the optical waveguide structure 1a in the related art. Please refer to Figure 1 , the optical waveguide structure 1a includes an optical waveguide 10a, an input grating 20a, and an output grating 30a. The input grating 20a and the output grating 30a are spaced apart on the same surface of the optical waveguide 10a. The input grating 20a is used to couple the image light LSa into the optical waveguide 10a, so that the image light LSa propagates in the optical waveguide 10a in the direction close to the output grating 30a, and the output grating 30a is used to couple the image light LSa out of the optical waveguide 10a.

[0049] When applying the optical waveguide structure 1a in the related art to an AR display device, there are at least the following problems. Specifically, when a user uses an AR display device, the number of image lights coupled out from the output grating 30a that can be received by the human eye is limited. That is, among all the image lights LSa coupled out from the output grating 30a, some image lights LSa can be received by the human eye. Define the output area corresponding to the image light LSa on the output grating 30a that can be received by the human eye as the receiving area 31a. During the process of the image light LSa propagating from the input grating 20a to the output grating 30a, some image lights LSa deviate from the preset propagation direction and shift towards the edge of the optical waveguide 10a, making it difficult for this part of the image light LSa to be coupled out of the optical waveguide 10a from the receiving area 31a and finally received by the human eye, resulting in a decrease in the brightness of the display image seen by the human eye.

[0050] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.

[0051] It should be noted that when a component is referred to as "fixed to" or "installed on" another component, it can be directly on the other component or there may also be an intermediate component. When a component is considered to be "disposed on" another component, it can be directly disposed on the other component or there may be an intermediate component at the same time. The term "and / or" used herein includes all and any combinations of one or more of the related listed items. The terms used in the description of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0052] In order to further elaborate on the technical means and effects adopted by the present application to achieve the predetermined purpose, the following detailed description of the present application is made in conjunction with the drawings and preferred embodiments.

[0053] Please refer to Figure 2 and Figure 3 As shown in FIGS. and, the optical waveguide structure 1 of the first embodiment of the present application includes an optical waveguide 10, and an input grating 20 and an output grating 30 which are spaced apart and located on the same surface of the optical waveguide 10. The input grating 20 is used to couple the image light LS into the optical waveguide 10, and the output grating 30 is used to couple the image light LS from the input grating 20 out of the optical waveguide 10, so that the image light LS is received by the human eye, thereby enabling the user to see the display screen formed by the image light LS.

[0054] The optical waveguide 10 includes a first light guiding portion 11 and a second light guiding portion 12 spliced with each other. The refractive index of the first light guiding portion 11 is less than that of the second light guiding portion 12, and the refractive index range of the second light guiding portion 12 is 1.3 - 2.5 (including the end values). The orthographic projections of the input grating 20 and the output grating 30 on the optical waveguide 10 in the thickness direction of the optical waveguide 10 are located on the first light guiding portion 11. Both the input grating 20 and the output grating 30 are disposed on the surface of the first light guiding portion 11. After the image light LS is coupled into the optical waveguide 10 from the input grating 20, it sequentially passes through the first light guiding portion 11, the second light guiding portion 12, and the first light guiding portion 11 and then is coupled out of the optical waveguide 10 from the output grating 30.

[0055] The optical waveguide 10 is generally in a rectangular thin plate-like structure, including a first surface 101 and a second surface 102 which are spaced apart and face away from each other. The input grating 20 and the output grating 30 are spaced apart and disposed on the first surface 101. The input grating 20 is generally in a circular thin plate-like structure, and the output grating 30 is generally in a rectangular thin plate-like structure. The connecting line of the geometric centers of the input grating 20 and the output grating 30 is parallel to the long side of the first surface 101 and is equidistant from the two long sides of the first surface 11. In other embodiments of the present application, the input grating 20 and the output grating 30 may have other geometric structures, such as a rhombus or a hexagon. In some implementation manners, as Figure 4 shown, the input grating 20 and the output grating 30 are disposed on different surfaces of the optical waveguide 10. The input grating 20 is located on the first surface 101, and the output grating 30 is located on the second surface 102.

[0056] The first light guide portion 11 includes a first part 111 and a second part 112 that are separated from each other. The first part 111 and the second part 112 are respectively connected to two ends of the second light guide portion 12 and are flush with the second light guide portion 12 in the thickness direction. The first part 111, the second light guide portion 12, and the second part 112 are all rectangular thin plate-like structures. The first part 111, the second light guide portion 12, and the second part 112 are spliced in sequence to form the optical waveguide 10. The thickness of the first part 111, the thickness of the second part 112, and the thickness of the second light guide portion 12 are the same. In the extending direction perpendicular to the thickness of the optical waveguide 10 (it can also be said that along the propagation direction of the image light LS in the optical waveguide 10, without considering the reflection direction of the image light LS in the optical waveguide 10), the width of the first part 111, the width of the second part 112, and the width of the second light guide portion 12 are the same. The coupling grating 20 is located on the surface of the first part 111, and the output coupling grating 30 is located on the surface of the second part 112, so that after the image light LS is coupled into the first part 111 from the coupling grating 20, it is conducted through the first part 111, the second light guide portion 12, and the second part 112 in sequence, and finally is coupled out of the second part 112 from the output coupling grating 30.

[0057] Please refer to Figure 5 , the first light guide portion 11 and the second light guide portion 12 are flush in the thickness direction of the optical waveguide 10. The first surface 101 and the second surface 102 are both composed of the first light guide portion 11 and the second light guide portion 12 together, and the first surface 101 and the second surface 102 are respectively basically smooth planes. The thickness of the first light guide portion 11 is equal to the thickness of the second light guide portion 12, so that the image light LS can be conducted forward after being alternately reflected by the first surface 101 and the second surface 102 respectively within the first light guide portion 11 and the second light guide portion 12.

[0058] The second light guide portion 12 includes a first side surface 121 and a second side surface 122 that connect the first light guide portion 11. The first side surface 121 and the second side surface 122 are located between the first surface 101 and the second surface 102 and are respectively connected to the first surface 101 and the second surface 102. In this embodiment, both the first side surface 121 and the second side surface 122 are planes. The first side surface 121 and the second side surface 122 are parallel to each other and are both perpendicular to the first surface 101. The first side surface 121 and the second side surface 122 are arranged at intervals in sequence in the direction from the coupling grating 20 to the output coupling grating 30.

[0059] Both the first light guide portion 11 and the second light guide portion 12 are transparent solid structures. The material of the second light guide portion 12 can be glass, plastic, or a combination of the two. In other embodiments, the first light guide portion 11 is a transparent solid structure, and the second light guide portion 12 is a transparent liquid structure. The material of the second light guide portion 12 includes water or oil. At this time, the second light guide portion 12 is located in a solid container, and the refractive index of the solid container is the same as the refractive index of the first light guide portion 11.

[0060] Please also refer to Figure 6 and Figure 7 In the optical waveguide structure 1 of the second embodiment of the present application, different from the first embodiment, both the first side surface 121 and the second side surface 122 are smooth curved surfaces. In some implementation manners, both the first side surface 121 and the second side surface 122 are spherical curved surfaces, and the curvature of the second side surface 122 is less than or equal to the curvature of the first side surface 121. The first side surface 121 and the second side surface 122 are curved towards the side of the coupling grating 30. Since both of the two opposite first side surface 121 and second side surface 122 of the second light guiding portion 12 are spherical curved surfaces, and the second light guiding portion 12 is made of a transparent material. A lens is an optical element made of a transparent substance (such as glass, crystal, etc.) and has two refractive curved surfaces. Therefore, the second light guiding portion 12 can be regarded as a lens structure, the first side surface 121 is the object side surface of the second light guiding portion 12, the second side surface 122 is the image side surface of the second light guiding portion 12, and the process of the image light LS being transmitted from the first portion 111 through the second light guiding portion 12 to the second portion 112 is equivalent to an imaging process of the second light guiding portion 12. The image light LS is a parallel light beam. Therefore, in the imaging process of the second light guiding portion 12, the object distance is infinite. In order to make the image light LS transmitted through the second light guiding portion 12 also be a parallel light beam, that is, in order to make the image distance in the imaging process of the second light guiding portion 12 be infinite, according to the imaging formula of the lens, the focal length of the second light guiding portion 12 should be designed to be infinite. From the lensmaker's equation, it can be deduced that the radius of curvature of the first side surface 121 and the radius of curvature of the second side surface 122 should satisfy the following relational expression:

[0061] n×(R2-R1 + d)-d = 0,

[0062] where n is the refractive index of the first light guiding portion 11, R1 is the radius of curvature of the first side surface 121, R2 is the radius of curvature of the second side surface 122, neither the radius of curvature R1 nor the radius of curvature R2 is infinite, and d is the shortest distance between the first side surface 121 and the second side surface 122. It can also be said that d is the distance between the first side surface 121 and the second side surface 122 on the line connecting the centers of the spheres of the first side surface 121 and the second side surface 122.

[0063] Since the first side surface 121 and the second side surface 122 of the second light guiding portion 12 are smooth spherical curved surfaces protruding in the same direction, and the curvature of the second side surface 122 is less than or equal to the curvature of the first side surface 121, when the curvature of the second side surface 122 is less than the curvature of the first side surface 121, the second light guiding portion 12 is a concave lens structure. A concave lens structure generally diverges a parallel light beam. Therefore, after the image light LS is transmitted through the second light guiding portion 12, the beam radius of the image light LS expands, so that the beam radius of the image light LS exiting from the coupling grating 30 will also expand accordingly, thereby realizing the effect of pupil dilation.

[0064] Please refer to Figure 8 Figure 8 , in the optical waveguide structure 1 of the third embodiment of the present application, different from the first and second embodiments, the first light guiding portion 11 is disposed around the second light guiding portion 12. In some implementation manners, the first light guiding portion 11 is not separated by the second light guiding portion 12. The first light guiding portion 11 has a rectangular opening, and the second light guiding portion 12 is a thin plate-like structure with a rectangular contour. The first light guiding portion 11 is connected around the outer edge of the second light guiding portion 12. Along the propagation direction of the image light LS in the optical waveguide 10 (without considering the reflection direction of the image light LS in the optical waveguide 10), the width of the second light guiding portion 12 is smaller than the width of the outer contour of the first light guiding portion 11. In this embodiment, both the first side surface 121 and the second side surface 122 are planes, the first side surface 121 is parallel to the second side surface 122, and both are perpendicular to the first surface 101.

[0065] Please refer to Figure 9 Figure 9 , in the optical waveguide structure 1 of the fourth embodiment of the present application, different from the third embodiment, both the first side surface 121 and the second side surface 122 are curved surfaces, and the radii of curvature of the first side surface 121 and the second side surface 122 can satisfy the relational expression in the second embodiment, so that the beam radius of the image light LS transmitted through the second light guiding portion 12 is enlarged to achieve a pupil expansion effect.

[0066] Please refer to Figure 3 , Figure 6 , Figure 8 and Figure 9 Figure 9 , in the above four embodiments, the second light guiding portion 12 further includes a third side surface 123 and a fourth side surface 124 that are relatively spaced apart. The third side surface 123 and the fourth side surface 124 are located between the first surface 101 and the second surface 102, and the third side surface 123 and the fourth side surface 124 are also located between the first side surface 121 and the second side surface 122. The first side surface 121, the third side surface 123, the second side surface 122, and the fourth side surface 124 are sequentially connected to form the side wall of the second light guiding portion 12. In the above four embodiments, both the third side surface 123 and the fourth side surface 124 are planes. The present application does not limit the shapes of the third side surface 123 and the fourth side surface 124. In other embodiments, the third side surface 123 and the fourth side surface 124 can be curved surfaces.

[0067] Please refer to again Figure 3, in order to enable more image light to exit from the area (receiving area 31) corresponding to the image light LS that can be received by the human eye on the output grating 30, and to increase the brightness of the display image seen by the human eye when using the display device, the optical waveguide 10 of the optical waveguide structure 1 in the embodiment of the present application includes a first light guiding portion 11 and a second light guiding portion 12, and the refractive index of the first light guiding portion 11 is less than that of the second light guiding portion 12. The second light guiding portion 12 is used to refract and transmit the image light LS, so that the image light LS shifts in a direction away from the edge of the optical waveguide 10, thereby reducing the degree of shift of the image light LS in the direction close to the edge of the optical waveguide 10, so as to increase the number of image light LS exiting from the receiving area 31, enabling the human eye to see more image light LS, and thus increasing the brightness of the display image seen by the human eye.

[0068] The optical waveguide structure in the embodiment of the present application can be applied to display devices using AR technology, such as AR near-eye display devices and AR head-up display devices.

[0069] The embodiment of the present application also provides a display device applying the above optical waveguide structure, including: a display for emitting image light; and the optical waveguide structure described in any of the above embodiments, the input grating is located on the optical path of the image light and is used to couple the image light into the optical waveguide.

[0070] The following will be described by taking the AR near-eye display device and the AR head-up display device applying the above optical waveguide structure as examples respectively.

[0071] Please refer to Figure 10 and Figure 11 , which is a schematic diagram of the AR near-eye display device 100 applying the optical waveguide structure 1 in the embodiment of the present application.

[0072] The AR near-eye display device 100 in the embodiment of the present application includes an optical waveguide structure 1, a display 2, and a collimating lens 3. The display 2 is used to emit image light LS, the optical waveguide structure 1 is located on the optical path of the image light LS, and both the input grating 20 and the output grating 30 are located on the first surface 101. The display 2 can be any one of a liquid crystal display, a fast response liquid crystal display, a liquid crystal on silicon display, a micro light emitting diode display, a digital light processing display, a laser beam scanning display, an active matrix organic light emitting diode display, and a silicon-based organic light emitting diode display, and the present application does not make any restrictions.

[0073] The collimating lens 3 is located between the display 2 and the coupling grating 20, and is spaced from the display 2 and the optical waveguide 10 respectively. The image light LS emitted by the display 2 is a non-parallel light beam, and the collimating lens 3 is used to convert the image light LS from the display 2 into a parallel light beam and then emit it to the coupling grating 20. That is, the coupling grating 20 is located on the optical path of the image light LS emitted by the collimating lens 3. The parallel light has a uniform light intensity distribution and a small divergence angle, which enables the parallel light to be more evenly distributed on the surface of the optical waveguide 10 before entering the optical waveguide 10. Converting the image light LS into a parallel light beam is beneficial to reducing the scattering when the image light LS is coupled into the optical waveguide 10 by the coupling grating 20 and improving the optical coupling efficiency. The polarization state of the image light LS can be a circular polarization state or a linear polarization state. The wavelength range of the image light LS is generally 400nm - 700nm (including the end values). The color of the image light LS can be formed by mixing red, green, and blue in different proportions. This application does not limit the polarization state, color, and wavelength of the image light LS.

[0074] Please refer to Figure 12 , which is a schematic diagram of the AR head-up display device 200 applying the optical waveguide structure 1 according to the embodiment of the present application.

[0075] In addition to the optical waveguide structure 1, the display 2, and the collimating lens 3, the AR head-up display device 200 according to the embodiment of the present application further includes an imaging medium 4. In the AR head-up display device 200, the coupling grating 20 and the decoupling grating 30 are located on different surfaces of the optical waveguide 10. The coupling grating 20 is located on the first surface 101, and the decoupling grating is located on the second surface 102. The imaging medium 4 is located on the optical path of the image light LS emitted by the decoupling grating 30, and is used to reflect the image light LS to the human eye so that the human eye can see the display image of the display 2. At the same time, the imaging medium 4 is also used to transmit external light, enabling the user to see the combination of the display image of the display 2 and the external scene, thereby achieving the purpose of augmented reality. The imaging medium 4 can be a plane mirror, a concave mirror, or a combination of multiple mirrors with different shapes. This application does not limit the shape and number of the imaging medium 4.

[0076] Those of ordinary skill in the art in this technical field should recognize that the above embodiments are only used to illustrate the present application, rather than to limit the present application. As long as within the scope of the substantial spirit of the present application, appropriate changes and variations made to the above embodiments fall within the scope of protection required by the present application.

Claims

1. An optical waveguide structure, characterized in that: It comprises an optical waveguide and an in-coupling grating and an out-coupling grating which are located on the same surface of the optical waveguide and are spaced apart from each other; The optical waveguide comprises a first light guide portion and a second light guide portion which are spliced ​​to each other, the refractive index of the first light guide portion is smaller than the refractive index of the second light guide portion, and the orthographic projections of the coupling-in grating and the coupling-out grating on the optical waveguide along the thickness direction of the optical waveguide are located on the first light guide portion; The coupling-in grating is used to couple the image light into the optical waveguide, so that the image light passes through the first light guide portion, the second light guide portion, and the first light guide portion in sequence, and then is coupled out of the optical waveguide from the coupling-out grating.

2. The optical waveguide structure according to claim 1, wherein: The optical waveguide comprises a first surface and a second surface which are spaced apart from each other, the first light guide portion and the second light guide portion are flush with each other in a thickness direction of the optical waveguide, and the first surface and the second surface are both constituted by the first light guide portion and the second light guide portion.

3. The optical waveguide structure according to claim 2, wherein: The second light guiding portion comprises a first side surface and a second side surface connected to the first light guiding portion, and the first side surface and the second side surface are sequentially arranged at intervals in a direction from the coupling-in grating to the coupling-out grating.

4. The optical waveguide structure according to claim 3, characterized in that: The first side surface and the second side surface are both planes, and the first side surface and the second side surface are parallel to each other.

5. The optical waveguide structure according to claim 4, characterized in that: The first side surface and the second side surface are perpendicular to the first surface.

6. The optical waveguide structure according to claim 3, wherein: The first side surface and the second side surface are both smooth curved surfaces, and the first side surface and the second side surface are bent toward one side of the outcoupling grating.

7. The optical waveguide structure according to claim 6, characterized in that The first side surface and the second side surface are both spherical surfaces, and the curvature of the second side surface is less than or equal to the curvature of the first side surface.

8. The optical waveguide structure according to claim 7, wherein: The optical waveguide structure satisfies the relationship: n×(R2-R1+d)-d=0, Wherein, n is the refractive index of the first light guiding portion, R1 is the curvature radius of the first side surface, R2 is the curvature radius of the second side surface, and d is the shortest distance between the first side surface and the second side surface.

9. The optical waveguide structure according to any one of claims 1 to 8, characterized in that: The refractive index of the second light guiding portion is in the range of 1.3-2.

5.

10. The optical waveguide structure according to any one of claims 1 to 8, characterized in that: The first light guiding part and the second light guiding part are both transparent solid structures.

11. The optical waveguide structure according to any one of claims 1 to 8, characterized in that: The first light guiding part is a transparent solid structure, and the second light guiding part is a transparent liquid structure.

12. The optical waveguide structure according to any one of claims 1 to 8, characterized in that: The first light guiding portion includes a first part and a second part separated from each other, the first part and the second part are respectively connected to the two ends of the second light guiding portion and are flush with the second light guiding portion in the thickness direction; the coupling-in grating is located on the surface of the first part, and the coupling-out grating is located on the surface of the second part, and the coupling-in grating is used to couple the image light into the first part, so that the image light passes through the first part, the second light guiding portion, and the second part in sequence, and then couples out of the second part from the coupling-out grating.

13. The optical waveguide structure according to any one of claims 1 to 8, characterized in that: The first light guiding portion is disposed around the second light guiding portion.

14. A display device, characterized in that: include: a display for emitting image light; as well as The optical waveguide structure according to any one of claims 1 to 13, wherein the coupling grating is located on an optical path of the image light, and is used to couple the image light into the optical waveguide.

15. The display device according to claim 14, characterized in that The head mounted display device further comprises a collimating lens, which is located between the display and the coupling-in grating and is used for converting the image light from the display into a parallel light beam and then emitting the parallel light beam to the coupling-in grating.

16. The display device according to claim 14, characterized in that The display device is an AR near-eye display device or an AR head-up display device.

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