Curved waveguide and manufacturing method thereof, eye tracking device, VR / AR device

Abstract

The application provides a curved waveguide and a manufacturing method thereof, an eyeball tracking device and a VR / AR device. The manufacturing method comprises the following steps: preparing a curved waveguide substrate; preparing a recess structure on the curved waveguide substrate; preparing a coupling-out glass sheet for reflecting light; connecting the coupling-out glass sheet in the recess structure; and filling the gap between the coupling-out glass sheet and the inner wall of the recess structure. The application can conveniently prepare a coupling-out reflection surface in the curved waveguide substrate, so that specific light propagating by total reflection in the curved waveguide substrate can be coupled out, or specific light directly irradiating on the coupling-out glass sheet can be reflected. The manufacturing method does not affect and change the overall structure shape and optical parameters of the curved waveguide substrate, and guarantees the structural reliability of the curved waveguide substrate. Compared with the method of splicing and gluing to form a reflection surface in the traditional method, the manufacturing method reduces the assembly process difficulty, and also effectively reduces the cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of eye tracking, in particular to a curved waveguide and a manufacturing method thereof, an eye tracking device and a VR / AR device. BACKGROUND

[0002] In a VR (Virtual Reality) and AR (Augmented Reality) display scheme, the viewing direction of the eyeball of a human eye needs to be acquired in real time, that is, eye movement tracking needs to be performed in real time, so as to adjust the display position of a virtual image in a virtual space according to the viewing direction of the human eye, to achieve a more realistic virtual reality experience.

[0003] In some current VR / AR schemes based on waveguide display, an infrared light source is arranged on a device, and an infrared reflecting surface is arranged in a waveguide. Infrared detection light can be coupled into the waveguide to propagate by total reflection, and is reflected by the infrared reflecting surface to be coupled out of the waveguide and irradiate to the human eye during the process of total reflection; the infrared detection light can also directly irradiate on the infrared reflecting surface and be reflected to the human eye.

[0004] The traditional way of preparing the infrared reflecting surface in the waveguide is: manufacturing a substrate, coating a film on the substrate, cutting the substrate, and bonding the cut substrates to each other to form a waveguide. In the current VR / AR scheme, the waveguide is generally a curved waveguide, and the cut substrates are bonded to each other to form a curved waveguide and meet the pre-designed optical parameters. This manufacturing method is extremely difficult. Therefore, in the field, how to prepare the reflecting surface in the curved waveguide is a technical problem to be solved. SUMMARY

[0005] Therefore, the present application provides a curved waveguide and a manufacturing method thereof, an eye tracking device and a VR / AR device, which can conveniently prepare a reflecting surface in a curved waveguide and do not affect the structure of the curved waveguide.

[0006] In a first aspect, the present application provides a manufacturing method of a curved waveguide, comprising the steps of: manufacturing a curved waveguide substrate; manufacturing a recess structure on the curved waveguide substrate; manufacturing a coupling-out glass sheet for reflecting light; connecting the coupling-out glass sheet in the recess structure; and filling the gap between the coupling-out glass sheet and the inner wall of the recess structure.

[0007] The present aspect can conveniently prepare a coupling-out reflecting surface in a curved waveguide substrate, so that specific light propagating by total reflection in the curved waveguide substrate can be coupled out, or specific light directly irradiating on the coupling-out sheet can be reflected. The manufacturing method does not affect and change the overall structure shape and optical parameters of the curved waveguide substrate, and ensures the structural reliability of the curved waveguide substrate. Compared with the method of splicing and gluing to form a reflecting surface in the traditional method, the manufacturing method reduces the assembly process difficulty, and also effectively reduces the cost.

[0008] With reference to the first aspect, in a possible implementation manner, the preparing the recessed structure on the curved waveguide substrate comprises: preparing a plurality of array-arranged recessed structures on the curved waveguide substrate; the preparing the coupling-out sheet for reflecting light comprises: preparing a plurality of the coupling-out sheets; and the connecting the coupling-out sheet in the recessed structure comprises: connecting the plurality of the coupling-out sheets one by one in the plurality of the recessed structures.

[0009] With reference to the first aspect, in a possible implementation manner, the preparing the recessed structure on the curved waveguide substrate comprises: preparing at least one positioning surface in the recessed structure; and the connecting the coupling-out sheet in the recessed structure comprises: abutting the coupling-out sheet on the positioning surface.

[0010] With reference to the first aspect, in a possible implementation manner, the preparing the coupling-out sheet for reflecting light comprises: respectively coating a reflecting film on opposite two surfaces of a glass substrate; and cutting the glass substrate coated with the film along a thickness direction to obtain the coupling-out sheet.

[0011] With reference to the first aspect, in a possible implementation manner, the cutting the glass substrate coated with the film along a thickness direction to obtain the coupling-out sheet comprises: uniformly cutting the glass substrate to form a plurality of the coupling-out sheets with the same shape and size.

[0012] With reference to the first aspect, in a possible implementation manner, the filling the gap between the coupling-out sheet and the inner wall of the recessed structure comprises: injecting glue into the recessed structure; and curing the glue in the recessed structure; wherein a difference between any two of the refractive index of the curved waveguide substrate, the refractive index of the coupling-out sheet and the refractive index of the glue is less than 0.1; and a difference between any two of the Abbe number of the curved waveguide substrate, the Abbe number of the coupling-out sheet and the Abbe number of the glue is less than 30.

[0013] With reference to the first aspect, in a possible implementation manner, after the filling the gap between the coupling-out sheet and the inner wall of the recessed structure, the manufacturing method further comprises: polishing the surface of the curved waveguide substrate.

[0014] With reference to the first aspect, in a possible implementation manner, the preparing the recessed structure on the curved waveguide substrate comprises: preparing a groove on the curved waveguide substrate; and the connecting the out-coupling piece in the recessed structure comprises: inserting the out-coupling piece into the groove.

[0015] With reference to the first aspect, in a possible implementation manner, the preparing the recessed structure on the curved waveguide substrate comprises: preparing an opening penetrating through a thickness direction of the curved waveguide substrate; and the connecting the out-coupling piece in the recessed structure comprises: inserting the out-coupling piece into the opening.

[0016] The second aspect provides a curved waveguide, comprising: a curved waveguide substrate, the curved waveguide substrate having a recessed structure; an out-coupling piece for reflecting light, the out-coupling piece being connected in the recessed structure; and a filler, the filler being filled in a gap between the out-coupling piece and an inner wall of the recessed structure.

[0017] The second aspect is a product corresponding to the first aspect, and the technical effects of the second aspect are not repeated here.

[0018] The third aspect provides an eye tracking device, comprising: a probe light source for emitting probe light; and the aforementioned curved waveguide, the probe light being coupled into the curved waveguide substrate to propagate by total reflection, or the illumination direction of the probe light source being towards the out-coupling piece, and the reflection direction of the out-coupling piece being towards a human eye.

[0019] The third aspect includes the second aspect, and the technical effects of the third aspect are not repeated here.

[0020] The fourth aspect provides a VR device, comprising: the aforementioned curved waveguide.

[0021] The fourth aspect includes the second aspect, and the technical effects of the fourth aspect are not repeated here.

[0022] The fifth aspect provides an AR device, comprising: the aforementioned curved waveguide.

[0023] The fifth aspect includes the second aspect, and the technical effects of the fifth aspect are not repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 Fig. 1 shows a method step schematic diagram of a curved waveguide manufacturing method provided by an embodiment of the present application.

[0025] Figure 2 Fig. 2 shows a method step schematic diagram of a curved waveguide manufacturing method provided by another embodiment of the present application.

[0026] Figure 3 Fig. 6 shows a schematic diagram of method steps of a method for manufacturing a curved waveguide according to an embodiment of the present application.

[0027] Figure 4 Fig. 6 shows a schematic diagram of method steps of a method for manufacturing a curved waveguide according to an embodiment of the present application.

[0028] Figure 5 Fig. 6 shows a schematic diagram of method steps of a method for manufacturing a curved waveguide according to an embodiment of the present application.

[0029] Figure 6 Fig. 6 shows a schematic diagram of method steps of a method for manufacturing a curved waveguide according to an embodiment of the present application.

[0030] Figure 7 Fig. 6 shows a schematic diagram of method steps of a method for manufacturing a curved waveguide according to an embodiment of the present application.

[0031] Figure 8 Fig. 6 shows a schematic diagram of method steps of a method for manufacturing a curved waveguide according to an embodiment of the present application.

[0032] Figure 9 Fig. 6 shows a schematic diagram of method steps of a method for manufacturing a curved waveguide according to an embodiment of the present application.

[0033] Figure 10 Fig. 1 shows a schematic diagram of a structure of a curved waveguide according to an embodiment of the present application.

[0034] Figure 11 Fig. 2 shows a schematic diagram of a structure of a curved waveguide according to an embodiment of the present application. Figure 10 Fig. 3 shows a schematic diagram of a structure of a curved waveguide according to an embodiment of the present application. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0036] Exemplary curved waveguide fabrication method

[0037] Figure 1 Fig. 6 shows a schematic diagram of method steps of a method for manufacturing a curved waveguide according to an embodiment of the present application. The present application provides a method for manufacturing a curved waveguide. In an embodiment, as shown in Fig. 6, the method comprises the following steps. Figure 1

[0038] ​Step 101, preparing a curved waveguide substrate.

[0039] Specifically, the surface of the curved waveguide substrate can be aspherical, cylindrical or free curved.

[0040] Step 102, preparing a recess structure on the curved waveguide substrate.

[0041] In this step, various process methods such as imprinting, etching and etching can be used to make and prepare the recess structure on the curved waveguide substrate.

[0042] Step 103, preparing a coupling-out glass sheet for reflecting light.

[0043] In this step, a whole substrate capable of reflecting light can be first made, and then the substrate is cut into a coupling-out glass sheet according to the size and shape of the recess structure. Specifically, the coupling-out glass sheet can be partially reflective and partially transmissive or fully reflective. The reflection band of the coupling-out glass sheet can be selected as needed, for example, when the curved waveguide is applied to the eyeball tracking function, the reflection band of the coupling-out glass sheet can be the infrared band, that is, the coupling-out glass sheet only reflects infrared detection light and transmits visible light.

[0044] Step 104, connecting the coupling-out glass sheet in the recess structure.

[0045] In this step, the coupling-out glass sheet is connected in the recess structure, and the coupling-out glass sheet serves as a reflecting element in the curved waveguide substrate. When there is light propagating by total reflection in the curved waveguide substrate or light directly irradiating on the coupling-out glass sheet, the total reflection propagation is broken by the coupling-out glass sheet or the light is reflected by the coupling-out glass sheet, and the light is reflected to the reflection direction of the coupling-out glass sheet. For example, when the curved waveguide is applied to the eyeball tracking function, the infrared detection light propagates by total reflection in the curved waveguide substrate or directly irradiates on the coupling-out glass sheet, the infrared detection light irradiates on the coupling-out glass sheet and is reflected, the reflection direction of the coupling-out glass sheet is towards the human eye, and the infrared detection light irradiates on the human eye.

[0046] Step 105, filling the gap between the coupling-out glass sheet and the inner wall of the recess structure.

[0047] In this step, glue such as UV glue can be injected into the gap to avoid the existence of air layer between the coupling-out glass sheet and the inner wall of the recess structure, which causes multiple refractions of light. When there is image light passing through the curved waveguide, the absence of gap between the coupling-out glass sheet and the inner wall of the recess structure can avoid multiple refractions of the image light and affect the visual effect.

[0048] The embodiment can conveniently prepare the coupling-out reflecting surface in the curved waveguide substrate, so that the specific light propagating by total reflection in the curved waveguide substrate can be coupled out, or the specific light directly irradiating on the coupling-out sheet can be reflected. The manufacturing method does not affect and change the overall structure shape and optical parameters of the curved waveguide substrate, and ensures the structural reliability of the curved waveguide substrate. Compared with the method of splicing and gluing to form the reflecting surface in the traditional method, the manufacturing method reduces the assembly process difficulty, and also effectively reduces the cost.

[0049] Figure 2 Fig. 2 shows a method step schematic diagram of a curved waveguide manufacturing method provided by another embodiment of the present application. In an embodiment, as shown in Fig. 2, step 102 includes: Figure 2

[0050] Step 1021, preparing a plurality of array-arranged recess structures on the curved waveguide substrate.

[0051] In this step, a plurality of recess structures can be manufactured and prepared on the curved waveguide substrate by using various process methods such as imprinting, etching, and etching, and the recess structures are arranged in an array form on the curved waveguide substrate during the preparation process.

[0052] Step 103 includes:

[0053] Step 1031, preparing a plurality of coupling-out sheets.

[0054] In this step, a whole sheet capable of reflecting light can be first manufactured, and then the sheet is cut into a plurality of slices as the plurality of coupling-out sheets.

[0055] Step 104 includes:

[0056] Step 1041, connecting the plurality of coupling-out sheets one by one in the plurality of recess structures.

[0057] In this step, the coupling-out sheets are connected in the recess structures, and the coupling-out sheets are arranged in an array form on the curved waveguide substrate.

[0058] In the embodiment, the curved waveguide with a plurality of reflecting elements can be manufactured, and the array-arranged plurality of coupling-out sheets can improve the coupling-out efficiency. For example, when the curved waveguide is applied to the eyeball tracking function, the plurality of coupling-out sheets can couple out more infrared detection light from the curved waveguide substrate, so that more infrared detection light irradiates on the human eye.

[0059] Figure 3 Fig. 4 shows a method step schematic diagram of a curved waveguide manufacturing method provided by another embodiment of the present application. In an embodiment, as shown in Fig. 4, step 102 includes: Figure 3

[0060] ​​Step 1022, preparing at least one positioning surface in the recessed structure.

[0061] Step 104 includes:

[0062] Step 1042, abutting the out-coupling glass sheet on the positioning surface.

[0063] In this embodiment, one surface of the out-coupling glass sheet can be tightly attached to the positioning surface, so as to determine the orientation of the out-coupling glass sheet; similarly, multiple surfaces of the out-coupling glass sheet can be tightly attached to multiple positioning surfaces. In the preparation process, the setting position and orientation of the out-coupling glass sheet are set according to the positioning surface according to the out-coupling requirement, and the preparation accuracy of the other surfaces of the recessed structure can be appropriately reduced, thereby effectively reducing the manufacturing difficulty and cost of the curved waveguide. In this embodiment, when the number of recessed structures and out-coupling glass sheets is multiple, multiple positioning surfaces can be prepared according to the preset trajectory, so that the multiple positioning surfaces corresponding to the multiple recessed structures are arranged according to the preset trajectory.

[0064] Figure 4 FIG. 6 shows a method step schematic diagram of a curved waveguide manufacturing method provided by another embodiment of the present application. In an embodiment, as shown in FIG. 6, step 103 includes: Figure 4

[0065] Step 1032, respectively coating a reflective film on the opposite two surfaces of the glass substrate.

[0066] Step 1033, cutting the glass substrate after coating along the thickness direction to obtain the out-coupling glass sheet.

[0067] Figure 5 FIG. 7 shows a method step schematic diagram of a curved waveguide manufacturing method provided by another embodiment of the present application. In an embodiment, as shown in FIG. 7, step 1033 includes: Figure 5

[0068] Step 10331, uniformly cutting the glass substrate to form multiple out-coupling glass sheets with the same shape and size.

[0069] This embodiment is applied to the case of multiple recessed structures and multiple out-coupling glass sheets, and the out-coupling glass sheets with the same shape and size are prepared, so as to realize mass production of the out-coupling glass sheets, thereby reducing the preparation cost.

[0070] Figure 6 FIG. 8 shows a method step schematic diagram of a curved waveguide manufacturing method provided by another embodiment of the present application. In an embodiment, as shown in FIG. 8, step 105 includes: Figure 6

[0071] Step 1051, injecting glue into the recessed structure.

[0072] Step 1052, curing the glue in the recessed structure.​​​

[0073] The difference between the refractive index of the curved waveguide substrate, the refractive index of the coupling-out glass sheet and the refractive index of the glue is less than 0.1; the difference between the Abbe number of the curved waveguide substrate, the Abbe number of the coupling-out glass sheet and the Abbe number of the glue is less than 30.

[0074] In the embodiment, the glue can effectively bond the coupling-out glass sheet and the curved waveguide substrate. Specifically, UV glue can be used, which has excellent optical performance and strong adhesion. The curved waveguide substrate, the coupling-out glass sheet and the glue with small difference in refractive index and Abbe number can reduce the effects of refraction, scattering and dispersion when light passes through the three media.

[0075] Figure 7 Fig. 6 shows a schematic diagram of method steps of a curved waveguide manufacturing method according to another embodiment of the present application. In an embodiment, as shown in Fig. 6, the curved waveguide manufacturing method comprises the following steps: Figure 7 After step 105, the curved waveguide manufacturing method further comprises:

[0076] Step 106: polishing the surface of the curved waveguide substrate.

[0077] In the embodiment, the polished curved waveguide substrate can avoid the coupling-out glass sheet or the glue protruding from the surface of the curved waveguide substrate and affecting the image display effect of the curved waveguide substrate.

[0078] Figure 8 Fig. 6 shows a schematic diagram of method steps of a curved waveguide manufacturing method according to another embodiment of the present application. In an embodiment, as shown in Fig. 6, the curved waveguide manufacturing method comprises the following steps: Figure 8 Step 102 comprises:

[0079] Step 1023: preparing a groove on the curved waveguide substrate.

[0080] Step 104 comprises:

[0081] Step 1043: inserting the coupling-out glass sheet into the groove.

[0082] In the embodiment, the recess structure is in the form of a groove, and the recess structure does not penetrate the curved waveguide substrate, thereby reducing the preparation difficulty and cost, and ensuring the overall structural reliability of the curved waveguide substrate.

[0083] Figure 9 Fig. 6 shows a schematic diagram of method steps of a curved waveguide manufacturing method according to another embodiment of the present application. In an embodiment, as shown in Fig. 6, the curved waveguide manufacturing method comprises the following steps: Figure 9 Step 102 comprises:

[0084] Step 1024: preparing an opening penetrating the thickness direction of the curved waveguide substrate on the curved waveguide substrate.

[0085] Step 104 includes:

[0086] Step 1044: Insert the coupled glass slide into the opening.

[0087] In this embodiment, the recessed structure is an opening penetrating the curved waveguide substrate, and the coupling glass plate matching the opening also penetrates the curved waveguide substrate, thereby increasing the coupling range of the coupling glass plate. For example, when this curved waveguide is used in eye-tracking functions, when the infrared detection light propagates through total internal reflection in the curved waveguide substrate or when the infrared detection light directly illuminates the coupling glass plate, the penetrating coupling glass plate can reflect more of the infrared detection light.

[0088] Exemplary curved waveguide

[0089] Figure 10 The diagram shown is a schematic diagram of a curved waveguide provided in an embodiment of this application. Figure 11 for Figure 10 A partial structural schematic diagram. This application provides a curved waveguide, in one embodiment, such as... Figure 10 and Figure 11 As shown, the curved waveguide includes a curved waveguide substrate 111, a coupling glass plate 113, and a filler 114. The curved waveguide substrate 111 has a recessed structure 112. The coupling glass plate 113 is used to reflect light and is connected in the recessed structure 112. The filler 114 fills the gap between the coupling glass plate 113 and the inner wall of the recessed structure 112, and the filler 114 can be made of UV adhesive.

[0090] This embodiment allows for the convenient fabrication of a coupling glass plate 113 within a curved waveguide substrate 111. The coupling glass plate 113 can couple out specific light propagating from total internal reflection within the curved waveguide substrate 111, or it can reflect specific light incident on it towards the human eye. The curved waveguide fabricated in this embodiment does not affect or alter the overall structural shape or optical parameters of the curved waveguide substrate 111, ensuring the structural reliability of the curved waveguide substrate. Compared to the traditional method of splicing and bonding to form a reflective surface, the curved waveguide fabricated in this embodiment reduces assembly process difficulty and effectively lowers costs.

[0091] Exemplary eye tracking device

[0092] This application also provides an eye-tracking device, which includes a detection light source and the aforementioned curved waveguide. The detection light source is used to emit detection light. The detection light is coupled into the curved waveguide substrate and propagates through total internal reflection, or the illumination direction of the detection light source is towards the coupling glass plate, and the reflection direction of the coupling glass plate is towards the human eye.

[0093] Specifically, the coupling-in end can be arranged on the curved waveguide substrate, and a coupling-in component can be arranged between the probe light source and the coupling-in end. The coupling-in component couples the probe light into the curved waveguide substrate for total reflection propagation. When the probe light for total reflection propagation meets the coupling-out sheet, the total reflection propagation of the probe light is broken and irradiated to the human eye. Alternatively, the probe light emitted by the probe light source is directly irradiated to the coupling-out sheet, and the coupling-out sheet reflects the probe light to the human eye.

[0094] Exemplary VR and AR devices

[0095] The application also provides a VR (Virtual Reality) device comprising the curved waveguide. In application, the VR device can couple out the specific light for total reflection propagation in the curved waveguide substrate or reflect the specific light directly irradiated on the coupling-out sheet, without affecting the normal display of the curved waveguide in the VR device.

[0096] The application also provides an AR (Augmented Reality) device comprising the curved waveguide. In application, the AR device can couple out the specific light for total reflection propagation in the curved waveguide substrate or reflect the specific light directly irradiated on the coupling-out sheet, without affecting the normal display of the curved waveguide in the AR device.

[0097] The above describes the basic principles of the application in combination with specific embodiments. However, it should be noted that the advantages, advantages, effects and the like mentioned in the application are only examples and are not limiting, and these advantages, advantages, effects and the like cannot be considered as the must-have of each embodiment of the application. In addition, the above specific details are only for the purpose of example and for the purpose of understanding, and the above details do not limit the application to the above specific details.

[0098] The block diagrams of the devices, apparatuses, equipment, systems involved in the application are only illustrative examples and are not intended to require or imply the connection, arrangement, configuration shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, equipment, systems can be connected, arranged, configured in any manner. Words such as "include", "contain", "have" and the like are open-ended words, which mean "including but not limited to", and can be used interchangeably. The words "or" and "and" used herein mean the word "and / or", and can be used interchangeably unless the context clearly indicates otherwise. The word "such as" used herein means the phrase "such as but not limited to", and can be used interchangeably.

[0099] It should also be noted that in the devices, equipment and methods of the application, each component or each step can be decomposed and / or recombined. These decompositions and / or recombination should be considered as equivalent solutions of the application.

[0100] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features of the invention herein.

[0101] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications or equivalent substitutions made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for fabricating a curved waveguide, characterized in that, The method comprises the steps of: preparing a curved waveguide substrate; preparing a recess structure on the curved waveguide substrate; preparing a coupling-out sheet for reflecting light rays; connecting the coupling-out sheet in the recess structure; and filling a gap between the coupling-out sheet and the inner wall of the recess structure. The step of filling the gap between the coupling-out sheet and the inner wall of the recess structure comprises: injecting glue into the recess structure; and curing the glue in the recess structure. The refractive index of the curved waveguide substrate, the refractive index of the coupling-out sheet, and the refractive index of the glue satisfy the condition that the difference between any two of the three refractive indices is less than 0.1; and the Abbe number of the curved waveguide substrate, the Abbe number of the coupling-out sheet, and the Abbe number of the glue satisfy the condition that the difference between any two of the three Abbe numbers is less than 30. The step of preparing a recess structure on the curved waveguide substrate comprises:

2. The method of claim 1, wherein, preparing a plurality of arrayed recess structures on the curved waveguide substrate. The step of preparing a coupling-out sheet for reflecting light rays comprises: preparing a plurality of coupling-out sheets. The step of connecting the coupling-out sheet in the recess structure comprises: connecting a plurality of coupling-out sheets one by one in a plurality of recess structures. The step of preparing a recess structure on the curved waveguide substrate comprises:

3. The method of claim 1, wherein, preparing at least one positioning surface in the recess structure. The step of connecting the coupling-out sheet in the recess structure comprises: abutting the coupling-out sheet against the positioning surface. The step of preparing a coupling-out sheet for reflecting light rays comprises:

4. The method of claim 1, wherein, respectively coating reflective films on opposite surfaces of a glass substrate; and cutting the glass substrate along the thickness direction after coating to obtain the coupling-out sheet. The step of cutting the glass substrate along the thickness direction after coating to obtain the coupling-out sheet comprises:

5. The method of claim 4, wherein, uniformly cutting the glass substrate to form a plurality of coupling-out sheets with the same shape and size. After the step of filling the gap between the coupling-out sheet and the inner wall of the recess structure, the method further comprises:

6. The method of claim 1, wherein, polishing the surface of the curved waveguide substrate. The step of preparing a recess structure on the curved waveguide substrate comprises:

7. The method of any one of claims 1-6, wherein, preparing a groove on the curved waveguide substrate. The step of connecting the coupling-out sheet in the recess structure comprises: inserting the coupling-out sheet into the groove. The step of preparing a recess structure on the curved waveguide substrate comprises:

8. The method of any one of claims 1-6, wherein, preparing an opening penetrating through the curved waveguide substrate in the thickness direction. The step of connecting the coupling-out sheet in the recess structure comprises: inserting the coupling-out sheet into the opening. The curved waveguide is prepared by the method of any one of claims 1-8, and the curved waveguide comprises:

9. A curved waveguide, characterized by, a curved waveguide substrate having a recess structure thereon; a coupling-out sheet for reflecting light rays, which is connected in the recess structure; and a filler filling a gap between the coupling-out sheet and the inner wall of the recess structure. The method comprises:

10. An eye tracking device, characterized in that a probe light source for emitting probe light; and a ​ The curved waveguide according to claim 9, wherein the probe light is totally reflected and propagates in the curved waveguide substrate, or an irradiation direction of the probe light source is toward the out-coupling plate, and a reflection direction of the out-coupling plate is toward the human eye.

11. A VR device, comprising: Comprising: The curved waveguide according to claim 9.

12. An AR device, comprising: Comprising: The curved waveguide according to claim 9.

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