Optical waveguide structure and display device

Abstract

The utility model relates to a kind of optical waveguide structure and display equipment, belong to the field of optical display, it includes waveguide base body, entrance pupil grating and exit pupil grating, entrance pupil grating is set on the waveguide base body, for the image light beam emitted by light machine is coupled into the waveguide base body, the length of entrance pupil grating along first direction is greater than the exit pupil diameter of light machine, the image light beam emitted by light machine can be coupled into at any position of entrance pupil grating along first direction, exit pupil grating is set on the waveguide base body, for the image light beam in the waveguide base body is emitted to human eye, the utility model has the relative position of light machine and optical waveguide structure can be flexibly fine-tuned according to actual, to be used for different whole machine architecture, improve the design space and debugging ability effect of whole machine architecture.

Description

Technical Field

[0001] This utility model relates to the technical field of optical display, and in particular to an optical waveguide structure and display device. Background Technology

[0002] Optical waveguide technology, as a core component of augmented reality (AR), virtual reality (VR), and mixed reality (MR) near-eye display systems, is widely used in various head-mounted display devices due to its high resolution, slim design, and excellent imaging quality. Optical waveguides primarily rely on gratings to couple light from the optical engine into the waveguide, and then transmit the image beam emitted by the optical engine to the human eye through internal reflection and expansion. This achieves a large field of view and high resolution while significantly reducing the size and weight of the device, thus improving wearing comfort.

[0003] Currently, most mainstream display systems adopt a binocular integrated waveguide architecture, which uses a single projection unit to provide images to both eyes simultaneously. The position and size of the entrance pupil of this type of waveguide are usually fixed in the design stage, and the entrance pupil size is close to the exit pupil size of the optical engine. In use, the optical engine aligns with the center of the entrance pupil of the waveguide to couple the image beam into the waveguide.

[0004] Because the positions and sizes of the optical engine and waveguide pupil are fixed, the relative positions between the optical engine and the waveguide cannot be flexibly adjusted according to actual needs. When there is a brightness difference between the left and right eyes, the optical engine cannot adjust its position to the left or right to adjust the brightness difference, which restricts the design space and debugging capabilities of the overall system architecture. Utility Model Content

[0005] In view of this, the purpose of this utility model is to provide an optical waveguide structure and display device to solve the technical problem that the relative position between the optomechanical system and the waveguide cannot be flexibly adjusted according to actual needs in the prior art, which restricts the design space and debugging capability of the overall system architecture.

[0006] This utility model provides an optical waveguide structure, comprising: Waveguide substrate; An entrance pupil grating is disposed on the waveguide substrate and is used to couple an image beam emitted by an optomechanical engine into the waveguide substrate. The length of the entrance pupil grating along the first direction is greater than the exit pupil diameter of the optomechanical engine, and the image beam emitted by the optomechanical engine can be coupled into the entrance pupil grating at any position along the first direction. An exit pupil grating is disposed on the waveguide substrate and is used to project an image beam from the waveguide substrate to the human eye.

[0007] Optionally, at least two exit pupil gratings are provided, and the entrance pupil grating is disposed between the two exit pupil gratings.

[0008] Optionally, it also includes a pupil grating, which is disposed on the waveguide substrate and can receive light from the entrance pupil grating. The pupil grating and the exit pupil grating are disposed correspondingly, and the image beam coupled into the waveguide substrate by the entrance pupil grating is transmitted to the corresponding exit pupil grating through the pupil grating.

[0009] Optionally, the length of the entrance pupil grating along the first direction is set to 1.5 to 3 times the diameter of the optomechanical exit pupil.

[0010] Optionally, it also includes a reflective structure for recovering unused light rays from the pupil grating and redirecting them into the waveguide substrate.

[0011] Optionally, the reflective structure includes a first reflector disposed on the side of the entrance pupil grating facing the optomechanism. The first reflector extends along the length of the entrance pupil grating and covers the area on the entrance pupil grating that does not correspond to the optomechanism.

[0012] Optionally, the reflective structure includes a second reflector disposed on the side of the waveguide substrate facing away from the optomechanical system, and the second reflector extends along the length direction of the entrance pupil grating.

[0013] This utility model also provides a display device, including the aforementioned optical waveguide structure.

[0014] Optionally, an optical engine is included, which is used to emit an image beam. The optical engine is disposed at and aligned with the entrance pupil grating. The diameter of the light spot formed by the image beam emitted by the optical engine on the exit pupil surface is smaller than the length of the entrance pupil grating along a first direction.

[0015] Optionally, at least two optical engines are provided, and multiple optical engines are arranged along the length direction of the entrance pupil grating, with all multiple optical engines aligned with the entrance pupil grating.

[0016] The technical solution of this utility model has the following advantages: 1. The optical waveguide structure provided by this utility model sets the length of the entrance pupil grating along the first direction to be greater than the exit pupil diameter of the optical engine, providing a continuous and adjustable tolerance range for the installation position of the optical engine. By increasing the size of the entrance pupil grating along the first direction, the image beam emitted by the optical engine is no longer limited to coupling into the waveguide substrate from a single center point in this direction, but can be coupled into the waveguide substrate at any position within the length range of the entrance pupil grating. Thus, during the assembly and subsequent debugging of the whole machine, the relative position of the optical engine and the optical waveguide structure can be flexibly fine-tuned according to the actual situation, enabling the optical waveguide structure to be used in different whole machine architectures, thereby improving the design space and debugging capability of the whole machine architecture.

[0017] 2. Due to fluctuations in the manufacturing process, when two exit pupil gratings are provided in the optical waveguide structure provided by this utility model, it is difficult to make the two exit pupil gratings completely consistent between the left and right eyes. This results in a brightness difference between the left and right eyes in actual display, affecting the user's visual experience and the consistency of the left and right eye images when wearing the device. However, by increasing the size of the entrance pupil grating along the first direction, when there is a brightness difference between the left and right eyes, the corresponding position of the optical engine on the entrance pupil grating can be adjusted to adjust the brightness difference between the left and right eyes, thereby improving the user's visual experience during wear, without the need for an additional structure to adjust the brightness difference between the left and right eyes. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a front view of the optical waveguide structure of this utility model; Figure 2 This is a front view of the optical waveguide structure with a pupil-expanding grating in this utility model. Figure 3 This is a schematic diagram of the optical path on the side of the optical waveguide structure in this utility model; Figure 4 This is a schematic diagram of the optical path on the side of the optical waveguide structure with a reflective structure in this utility model; Figure 5 This is a schematic diagram of another embodiment of the reflective structure in this utility model; Figure 6 This is a schematic diagram of another embodiment of the reflective structure in this utility model; Figure 7 This is a schematic diagram of the multi-optical engine structure in this utility model.

[0020] Explanation of reference numerals in the attached figures: 1. Waveguide substrate; 2. Entrance pupil grating; 3. Exit pupil grating; 4. Dilated pupil grating; 5. Optomechanical system; 6. Reflection structure; 61. First reflector; 62. Second reflector. Detailed Implementation

[0021] The specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the description of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0022] Unless otherwise explicitly specified and limited, the terms "setup," "installation," and "connection" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of these terms based on the specific circumstances.

[0023] The terms “upper,” “lower,” “left,” “right,” “front,” “back,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of description and simplification, 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 utility model.

[0024] In the diagram, the direction indicated by arrow X is the first direction, and the direction perpendicular to the direction indicated by arrow X is the second direction.

[0025] The terms “first,” “second,” “third,” etc., are used merely to distinguish elements with similar attributes, not to indicate or imply relative importance or a specific order.

[0026] The terms “include,” “comprising,” or any other variation thereof are intended to cover non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0027] Example 1 Reference Figures 1-7As shown, this utility model provides an optical waveguide structure, including a waveguide substrate 1, an entrance pupil grating 2, and an exit pupil grating 3. The waveguide substrate 1 is made of planar glass or resin. The entrance pupil grating 2 is disposed on the waveguide substrate 1. An optical engine 5 is aligned with the entrance pupil grating 2. The entrance pupil grating 2 is used to couple the image beam emitted by the optical engine 5 into the waveguide substrate 1. The length of the entrance pupil grating 2 along a first direction is greater than the exit pupil diameter of the optical engine 5. The exit pupil diameter of the optical engine 5 refers to the diameter of the light spot formed by the image beam emitted by the optical engine 5 at the exit pupil surface, i.e., the optimal observation position, along the first direction. The image beam emitted by the optical engine 5 can be coupled into the entrance pupil grating 2 at any position along the first direction. The optical engine 5 can adjust its position along the length direction of the entrance pupil grating 2, thereby changing the alignment position of the entrance pupil grating 2. The exit pupil grating 3 is disposed on the waveguide substrate 1 and has a certain gap with the entrance pupil grating 2. The exit pupil grating 3 is used to couple out the image beam coupled into the waveguide substrate 1 by the entrance pupil grating 2 and emit it into the human eye.

[0028] The length of the entrance pupil grating 2 along the first direction is set to be greater than the exit pupil diameter of the optical engine 5, providing a continuous and adjustable tolerance range for the installation position of the optical engine 5. By increasing the size of the entrance pupil grating 2 along the first direction, the image beam emitted by the optical engine 5 is no longer limited to coupling into the waveguide substrate 1 from a single center point in this direction, but can be coupled into the waveguide substrate 1 at any position within the length range of the entrance pupil grating 2. Thus, during the assembly and subsequent debugging of the whole machine, the relative position of the optical engine 5 and the optical waveguide structure can be flexibly fine-tuned according to the actual situation, enabling the optical waveguide structure to be used in different whole machine architectures, thereby improving the design space and debugging capability of the whole machine architecture.

[0029] Specifically, the length of the entrance pupil grating 2 along the first direction is set to 1.5 to 3 times the length of the exit pupil diameter of the optomechanical 5. There is one entrance pupil grating 2. To adapt to the structural and layout requirements of different systems, the geometry of the entrance pupil grating 2 is not limited. It can be rectangular, elliptical, strip-shaped, asymmetrical polygon, etc. The specific shape can be designed and customized according to the optical path layout or spatial constraints of the system, which has high flexibility and scalability.

[0030] The exit pupil grating 3 can be set to one or two, as shown in the reference. Figure 1 As shown, when there are two exit pupil gratings 3, the two exit pupil gratings 3 are located on both sides of the entrance pupil grating 2, and the entrance pupil grating 2 is located between the two exit pupil gratings 3. The central axis of the two exit pupil gratings 3 waveguide structures is symmetrically arranged, and the entrance pupil grating 2 is located on the central axis, thereby realizing binocular waveguide.

[0031] Due to fluctuations in the manufacturing process, when there are two exit pupil gratings 3, it is difficult to make them completely consistent between the left and right eyes. This results in a brightness difference between the left and right eyes in actual display, affecting the user's visual experience and the consistency of the images between the left and right eyes when wearing the device. However, by increasing the size of the entrance pupil grating 2 along the first direction, when there is a brightness difference between the left and right eyes, the corresponding position of the optical engine 5 on the entrance pupil grating 2 can be adjusted to change the brightness difference between the left and right eyes, making the brightness of the left and right eyes consistent and improving the user's visual experience during wear, without the need for additional structures to adjust the brightness difference between the left and right eyes.

[0032] As another implementation method, refer to Figure 2 As shown, the optical waveguide structure also includes a pupil grating 4. The pupil grating 4 is disposed on the waveguide substrate 1 and can receive light from the entrance pupil grating 2. When there is one exit pupil grating 3, there is one corresponding pupil grating 4. When there are two exit pupil gratings 3, there are two pupil gratings 4. The two pupil gratings 4 and the exit pupil gratings 3 are arranged in a one-to-one correspondence. The image beam coupled into the waveguide substrate 1 by the entrance pupil grating 2 is first transmitted to the pupil grating 4 and then to the corresponding exit pupil grating 3. The pupil grating 4 can receive the image beam coupled into the waveguide substrate 1 by the optomechanical 5 at any position of the entrance pupil grating 2.

[0033] As a specific implementation, it also includes a reflection structure 6, which is disposed at the entrance pupil grating 2. The reflection structure 6 is used to recover the unused light rays at the entrance pupil grating 2 and redirect the image beam emitted by the optomechanical 5 into the waveguide substrate 1. By setting the reflection structure 6, it is possible to capture the light rays that were originally lost due to the diffraction characteristics of the entrance pupil grating 2 and were not effectively coupled into the waveguide substrate 1, that is, the entrance pupil outgoing light from the surface of the entrance pupil grating 2 and the entrance pupil transmitted light that passed through the entrance pupil grating 2. This allows these unused light rays to still enter the corresponding expanding pupil grating 4 after one or more reflections, reducing the energy loss caused by the zeroth order or second order diffraction and improving the efficiency of the waveguide.

[0034] Specifically, refer to Figure 4 As shown, the reflection structure 6 includes a first reflector 61, which is configured as a mirror. The first reflector 61 is disposed on the side of the entrance pupil grating 2 facing the optical engine 5. The first reflector 61 extends along the length of the entrance pupil grating 2 and covers the area on the entrance pupil grating 2 that does not correspond to the optical engine 5. Specifically, the area on the entrance pupil grating 2 covered by the projection of the optical engine 5 along the second direction is not covered by the first reflector 61, so that the area of ​​the optical engine 5 facing the entrance pupil grating 2 is not blocked by the first reflector 61. This ensures that the image beam emitted by the optical engine 5 can be coupled into the entrance pupil grating 2, and that the lost light can still enter the corresponding expanding pupil grating 4 and be output after one or more reflections, thereby improving the efficiency of the waveguide.

[0035] In other embodiments, refer to Figure 5 As shown, the reflection structure 6 includes a second reflector 62, which is disposed on the side of the waveguide substrate 1 facing away from the optomechanical 5. The second reflector 62 is also configured as a mirror and extends along the length direction of the entrance pupil grating 2. The second reflector 62 covers the corresponding entrance pupil grating 2 area on the waveguide substrate 1, so that the length of the second reflector 62 along the first direction is the same as that of the entrance pupil grating 2, and the starting position is also the same. When the image beam emitted by the optomechanical 5 is coupled into the entrance pupil grating 2, the entrance pupil transmitted light that passes through the entrance pupil grating 2 can be reflected by the second reflector 62 once or multiple times and enter the corresponding expanding pupil grating 4, thereby improving the efficiency of the waveguide.

[0036] In other embodiments, refer to Figure 6 As shown, the reflection structure 6 includes a first reflector 61 and a second reflector 62. The first reflector 61 is disposed on the side of the entrance pupil grating 2 facing the optomechanism 5. The first reflector 61 extends along the length of the entrance pupil grating 2 and covers the non-corresponding coupling area on the entrance pupil grating 2 that is coupled to the optomechanism 5. The second reflector 62 is disposed on the side of the waveguide substrate 1 facing away from the optomechanism 5. The second reflector 62 is also configured as a reflector. The second reflector 62 extends along the length of the entrance pupil grating 2 and covers the corresponding area of ​​the entrance pupil grating 2 on the waveguide substrate 1, thereby maximizing the theoretical waveguide efficiency.

[0037] Example 2 Reference Figure 3 and Figure 7 As shown, this embodiment provides a display device, including the optical waveguide structure in embodiment 1, and also includes an optical engine 5. The optical engine 5 is used to emit an image beam. The optical engine 5 is disposed at the entrance pupil grating 2 and aligned with the entrance pupil grating 2. The diameter of the light spot formed by the image beam emitted by the optical engine 5 on the exit pupil surface is smaller than the length of the entrance pupil grating 2 along the first direction. The optical engine 5 can adjust its position along the length direction of the entrance pupil grating 2, so that the image beam emitted by the optical engine 5 is no longer limited to coupling into the waveguide substrate 1 from only a single center point in this direction, but can couple into the waveguide substrate 1 at any position within the length range of the entrance pupil grating 2. Thus, during the assembly and subsequent debugging of the whole machine, the relative position of the optical engine 5 and the optical waveguide structure can be flexibly fine-tuned according to the actual situation, which can be used for different whole machine architectures, improving the design space and debugging capability of the whole machine architecture.

[0038] In this embodiment, the optical engine 5 is provided with one or at least two, as shown in the reference. Figure 7 As shown, when at least two optical engines 5 are provided, multiple optical engines 5 are arranged along the length direction of the entrance pupil grating 2, and multiple optical engines 5 are aligned with the entrance pupil grating 2, thereby significantly improving the brightness of the waveguide display.

[0039] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0040] The above description is only a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model.

Claims

1. An optical waveguide structure, characterized in that, include: Waveguide substrate; An entrance pupil grating is disposed on the waveguide substrate and is used to couple an image beam emitted by an optomechanical engine into the waveguide substrate. The length of the entrance pupil grating along the first direction is greater than the exit pupil diameter of the optomechanical engine, and the image beam emitted by the optomechanical engine can be coupled into the entrance pupil grating at any position along the first direction. An exit pupil grating is disposed on the waveguide substrate and is used to project an image beam from the waveguide substrate to the human eye.

2. The optical waveguide structure as described in claim 1, characterized in that, At least two exit pupil gratings are provided, and the entrance pupil grating is disposed between the two exit pupil gratings.

3. The optical waveguide structure as described in claim 1, characterized in that, It also includes a pupil grating, which is disposed on the waveguide substrate and can receive light from the entrance pupil grating. The pupil grating and the exit pupil grating are disposed correspondingly. The image beam coupled into the waveguide substrate by the entrance pupil grating is transmitted to the corresponding exit pupil grating through the pupil grating.

4. The optical waveguide structure as described in claim 1, characterized in that, The length of the entrance pupil grating along the first direction is set to 1.5 to 3 times the diameter of the optomechanical exit pupil.

5. The optical waveguide structure as described in claim 1, characterized in that, It also includes a reflective structure for recovering unused light rays from the pupil grating and redirecting them into the waveguide substrate.

6. The optical waveguide structure as described in claim 5, characterized in that, The reflective structure includes a first reflector, which is disposed on the side of the entrance pupil grating facing the optical engine. The first reflector extends along the length of the entrance pupil grating and covers the area on the entrance pupil grating that does not correspond to the optical engine.

7. The optical waveguide structure as described in claim 5 or 6, characterized in that, The reflection structure includes a second reflector, which is disposed on the side of the waveguide substrate facing away from the optomechanical system and extends along the length direction of the entrance pupil grating.

8. A display device, characterized in that, Includes the optical waveguide structure described in any one of claims 1-7.

9. The display device as claimed in claim 8, characterized in that, The system includes an optical engine for emitting an image beam. The optical engine is located at and aligned with the entrance pupil grating. The diameter of the light spot formed by the image beam emitted by the optical engine on the exit pupil surface is smaller than the length of the entrance pupil grating along a first direction.

10. The display device as claimed in claim 9, characterized in that, At least two optical engines are provided, and multiple optical engines are arranged along the length direction of the entrance pupil grating, with all multiple optical engines aligned with the entrance pupil grating.

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