Optical transmission device and head-mounted display device
By stacking and matching the diffraction optical waveguide with the geometric optical waveguide, the problem of low coupling and pupil diffraction optical waveguide in the prior art is solved, and the optical efficiency and visual experience of optical transmission devices are improved.
Patent Information
- Application Number
- CN202311817738.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-26
- Publication Date
- 2025-06-27
AI Technical Summary
The existing diffraction light waveguide coupling and pupil dilation efficiency are low, resulting in low optical efficiency and affecting the imaging effect of augmented reality devices.
By combining the diffraction optical waveguide and the geometric optical waveguide, the coupling efficiency and pupil diffraction efficiency of the diffraction optical waveguide are improved by utilizing the compact volume of the diffraction optical waveguide and the high optical utilization rate of the geometric optical waveguide.
It achieves the improvement of optical efficiency of optical transmission devices, improves the user's visual experience, and reduces process difficulty.
Smart Images
Figure CN120215007A_ABST
Abstract
Description
Technical Field
[0001] Embodiments of the present application relate to the field of optical imaging technologies, and more specifically, to an optical transmission device and a head-mounted display device. Background Art
[0002] Currently, optical waveguides are one of the mainstream technical solutions for realizing Augmented Reality (AR). Diffractive optical waveguides are widely used and are the core components of AR products. In related technologies, diffractive optical waveguides use diffractive elements such as gratings as the light coupling and pupil expansion devices. However, existing coupling devices have the problem of low coupling and pupil expansion efficiency, which results in low optical efficiency of diffractive optical waveguides and affects the imaging effect. Summary of the Invention
[0003] The purpose of the present application is to provide a new technical solution for an optical transmission device and a head-mounted display device.
[0004] According to a first aspect of the present application, an optical transmission device is provided. The optical transmission device includes a first optical waveguide and a second optical waveguide stacked on top of each other. In the stacking direction, the light coupling portions of the first optical waveguide and the second optical waveguide are opposite to each other;
[0005] The first optical waveguide is configured to couple light in and expand the pupil in at least one dimensional direction and then transmit the light to the second optical waveguide;
[0006] The second optical waveguide is configured to receive the light transmitted by the first optical waveguide, expand the pupil in another dimensional direction, and then couple the light out;
[0007] Wherein, one of the first optical waveguide and the second optical waveguide is a diffractive optical waveguide, and the other is a geometric optical waveguide.
[0008] Optionally, the first optical waveguide and the second optical waveguide are spaced apart in the stacking direction to form a refractive index difference.
[0009] Optionally, the spacing size between the first optical waveguide and the second optical waveguide is 0.01 mm to 0.1 mm.
[0010] Optionally, at least one layer of the first optical waveguide and the second optical waveguide is provided respectively.
[0011] Optionally, the first optical waveguide includes a first light coupling portion and a first light coupling-out portion;
[0012] The second optical waveguide includes a second light coupling portion and a second light coupling-out portion;
[0013] In the stacking direction, the first light coupling-out portion is opposite to the second light coupling portion.
[0014] Optionally, the first optical waveguide is a geometric optical waveguide, and the second optical waveguide is a diffractive optical waveguide.
[0015] Optionally, the first optical waveguide is a diffractive optical waveguide, and the second optical waveguide is a geometric optical waveguide.
[0016] Optionally, the light-coupling portion of the geometric optical waveguide is a geometric coupling structure, and the light-emitting portion of the geometric optical waveguide is a diffractive optical structure.
[0017] Optionally, the geometric coupling structure includes a coupling prism or a coupling inclined surface, and the diffractive optical structure is a one-dimensional grating.
[0018] Optionally, both the light-coupling portion and the light-emitting portion of the diffractive optical waveguide are diffractive optical structures, and their grating vectors and periods are the same.
[0019] Optionally, the light-coupling portion and the light-emitting portion of the diffractive optical waveguide are a single one-dimensional grating or a combination of multiple one-dimensional gratings.
[0020] Optionally, the light-coupling portion and the light-emitting portion of the diffractive optical waveguide form a closed grating vector polygon.
[0021] According to a second aspect of the present application, there is provided a head-mounted display device, including:
[0022] An optical engine; and
[0023] The optical transmission device as described in the first aspect, where the optical engine is opposite to the light-coupling portion of the first optical waveguide.
[0024] One beneficial effect of the embodiment of the present application is:
[0025] The embodiment of the present application provides an optical transmission device. By stacking and combining a diffractive optical waveguide and a geometric optical waveguide, the characteristics of the compact volume of the diffractive optical waveguide and the high optical utilization rate of the geometric optical waveguide can be combined, the light-coupling efficiency and the pupil expansion efficiency can be improved, and thus the optical efficiency of the optical transmission device can be improved.
[0026] Through the following detailed description of the exemplary embodiments of the present specification with reference to the accompanying drawings, other features and advantages of the present specification will become clear. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The drawings incorporated in the specification and constituting a part of the specification illustrate embodiments of the present specification, and together with the description are used to explain the principles of the present specification.
[0028] Figure 1 It is a schematic structural diagram of the optical transmission device provided by the embodiment of the present application;
[0029] Figure 2 The top view of the first optical waveguide provided by the embodiment of the present application;
[0030] Figure 3 The top view of the second optical waveguide provided by the embodiment of the present application.
[0031] Explanation of reference numerals:
[0032] 10. First optical waveguide; 11. First coupling-in part; 12. First coupling-out part; 20. Second optical waveguide; 21. Second coupling-in part; 22. Second coupling-out part; 30. Optical engine. Detailed implementation manners
[0033] Now, various exemplary embodiments of the present application will be described in detail with reference to the accompanying drawings. It should be noted that: unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps set forth in these embodiments do not limit the scope of the present application.
[0034] The following description of at least one exemplary embodiment is merely illustrative in nature and in no way limits the present application, its application, or its use.
[0035] Techniques and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques and devices should be regarded as part of the specification.
[0036] In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values.
[0037] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.
[0038] Next, with reference to the accompanying drawings, the optical transmission device and the head-mounted display device provided by the embodiments of the present application will be described in detail.
[0039] According to one aspect of the embodiments of the present application, an optical transmission device is provided, and the optical transmission device can be applied to the augmented reality technology.
[0040] The embodiments of the present application provide an optical transmission device. Refer to Figures 1 to 3, the optical transmission device includes a first optical waveguide 10 and a second optical waveguide 20 arranged in a stacked manner. In the stacking direction, the coupling-in portions of the first optical waveguide 10 and the second optical waveguide 20 are opposite to each other. The first optical waveguide 10 is configured to couple light in and expand the pupil along at least one dimensional direction and then transmit the light to the second optical waveguide 20; the second optical waveguide 20 is configured to receive the light transmitted by the first optical waveguide 10, expand the pupil of the light in another dimensional direction, and then couple the light out. Wherein, one of the first optical waveguide 10 and the second optical waveguide 20 is a diffractive optical waveguide, and the other is a geometric optical waveguide.
[0041] It should be noted that the diffractive optical waveguide itself has the problem of low optical utilization efficiency. The reason is that on the diffractive optical waveguide, after the coupling grating couples the light from the outside into the waveguide, since some of the total reflection light will pass through the coupling grating again, resulting in the leakage of this part of the light through the coupling grating, and this phenomenon will affect the picture display performance of the augmented reality (AR) device. Therefore, it needs to be improved.
[0042] According to the optical transmission device provided by the embodiments of the present application, by stacking and combining the diffractive optical waveguide and the geometric optical waveguide, the characteristics of the compact volume of the diffractive optical waveguide and the high optical utilization efficiency of the geometric optical waveguide can be combined, so as to improve the light coupling efficiency and pupil expansion efficiency, and thus the optical efficiency of the optical transmission device can be improved.
[0043] The optical transmission device provided by the embodiments of the present application can use any one of the diffractive optical waveguide and the geometric optical waveguide as the coupling-in waveguide, which can couple in the light and expand the pupil along at least one dimensional direction, and then use the other of the diffractive optical waveguide and the geometric optical waveguide as the coupling-out waveguide to propagate the light, expand the pupil in another dimensional direction, and then couple the light out to form an image in the human eye. It can be seen that the combination of the two optical waveguides can achieve the two-dimensional pupil expansion effect of the light, improve the coupling efficiency and pupil expansion efficiency, and improve the user's visual experience.
[0044] In some examples of the present application, refer to Figure 1 , the first optical waveguide 10 and the second optical waveguide 20 are arranged at intervals in the stacking direction to form a refractive index difference.
[0045] Refer to Figure 1 , an air gap can be formed between the first optical waveguide 10 and the second optical waveguide 20 to form a refractive index difference. In this way, the light emitted from the first optical waveguide 10 can be transmitted into the second optical waveguide 20 for propagation.
[0046] Optionally, the interval size between the first optical waveguide 10 and the second optical waveguide 20 can be set to 0.01 mm to 0.1 mm.
[0047] In one example, the spacing between the first optical waveguide 10 and the second optical waveguide 20 is 0.05 mm.
[0048] It should be noted that the first optical waveguide 10 and the second optical waveguide 20 can be connected together by edge gluing, and an air gap of a certain size can be formed therebetween.
[0049] In some examples of the present application, at least one layer is provided for each of the first optical waveguide 10 and the second optical waveguide 20.
[0050] By increasing the number of layers of the first optical waveguide 10 and / or the second optical waveguide 20, the optical efficiency of the entire optical transmission device can be improved, and the imaging effect can be enhanced.
[0051] In some examples of the present application, refer to Figure 2 , the first optical waveguide 10 includes a first coupling-in portion 11 and a first coupling-out portion 12. Refer to Figure 3 , the second optical waveguide 20 includes a second coupling-in portion 21 and a second coupling-out portion 22. In the stacking direction, the first coupling-out portion 12 of the first optical waveguide 10 is opposite to the second coupling-in portion 21.
[0052] According to the above example, the first coupling-out portion 12 on the first optical waveguide 10 is opposite to the second coupling-in portion 21 of the second optical waveguide 20. In this way, the light emitted from the first optical waveguide 10 can enter the second optical waveguide 20 as completely as possible for propagation and pupil expansion in another dimensional direction.
[0053] Among them, the first coupling-in portion 11 on the first optical waveguide 10 should be opposite to the external optical engine 30 so that all the light emitted from the optical engine 30 is coupled into the first optical waveguide 10.
[0054] In some examples of the present application, refer to Figure 1 , the first optical waveguide 10 is a geometric optical waveguide, and the second optical waveguide 20 is a diffractive optical waveguide.
[0055] That is to say, it can be designed that the geometric optical waveguide is used as the coupling-in waveguide of the entire optical transmission device, which undertakes the functions of coupling-in and one-dimensional pupil expansion. At this time, the diffractive optical waveguide is the coupling-out waveguide of the entire optical transmission device, which undertakes the functions of coupling-out and one-dimensional pupil expansion. On this basis, the size of the geometric optical waveguide is the same as the size of the coupling-in portion of the diffractive optical waveguide.
[0056] It should be noted that using the geometric optical waveguide as the coupling-in waveguide of the entire optical transmission device can well improve the coupling-in efficiency, thereby better improving the optical utilization rate.
[0057] In some examples of the present application, refer toFigure 1 , the first optical waveguide 10 is a diffractive optical waveguide, and the second optical waveguide 20 is a geometric optical waveguide.
[0058] That is to say, it is also possible to design the diffractive optical waveguide as the input waveguide of the entire optical transmission device, which undertakes the functions of input coupling and one-dimensional pupil expansion. At this time, the geometric optical waveguide is the output waveguide of the entire optical transmission device, which undertakes the functions of output coupling and one-dimensional pupil expansion.
[0059] In some examples of the present application, the input part of the geometric optical waveguide is a geometric input structure, and the output part of the geometric optical waveguide is a diffractive optical structure.
[0060] Optionally, the geometric input structure includes, for example, an input prism or an input bevel. The diffractive optical structure is a one-dimensional grating.
[0061] In the case where the geometric input optical waveguide is used as the input waveguide, the geometric input structure on the geometric optical waveguide couples the light and then propagates it by total reflection to the output part. After passing through the diffractive optical structure of the output part, pupil expansion in, for example, one dimension direction is performed. At this time, a one-dimensional grating can be arranged at the output part. The production of the one-dimensional grating is relatively simple, which can reduce the cost and the process difficulty. At the same time, the input part and the output part of the diffractive optical waveguide, especially the output part, can also be a one-dimensional grating. In this way, the optical transmission device can achieve the two-dimensional pupil expansion effect through the one-dimensional gratings at two positions. There is no need to introduce a two-dimensional grating in the entire optical transmission device.
[0062] In some examples of the present application, both the input part and the output part of the diffractive optical waveguide are diffractive optical structures, and their grating vectors and periods are the same.
[0063] That is to say, for the diffractive optical waveguide, the input part and the output part thereon can be designed as the same grating. This can reduce the manufacturing difficulty of the diffractive optical waveguide.
[0064] Optionally, the input part and the output part of the diffractive optical waveguide are a single one-dimensional grating or a combination of multiple one-dimensional gratings.
[0065] In the embodiments of the present application, by combining the diffractive optical waveguide and the geometric optical waveguide, two-dimensional pupil expansion can be achieved without using a two-dimensional grating. This can reduce the process difficulty.
[0066] In some examples of the present application, the input part and the output part of the diffractive optical waveguide form a closed grating vector polygon.
[0067] It should be noted that the direction of the one-dimensional grating vector is perpendicular to the grating lines, which is the direction of its periodic change, and its length is equal to the reciprocal of the grating period.
[0068] Optionally, the gratings of the light coupling portion and the light output portion of the diffractive optical waveguide are one-dimensional gratings, and the grating period can be designed to be between 200 nm and 600 nm.
[0069] The optical transmission device provided by the embodiments of the present application can be applied to the optical waveguide element (lens) in a head-mounted display device. The head-mounted display device is, for example, an AR display device, and of course, it can also be an MR display device or an XR display device.
[0070] According to another aspect of the present application, a head-mounted display device is further provided. The head-mounted display device includes: Refer to Figure 1 , an optical engine 30 and the optical transmission device as described above, and the optical engine 30 is opposite to the light coupling portion of the first optical waveguide 10.
[0071] Among them, the optical engine 30 and the optical transmission device are, for example, arranged in one-to-one correspondence.
[0072] Among them, the optical transmission device can be, for example, set to two, respectively corresponding to the left eye and the right eye of the user.
[0073] In one example, the first optical waveguide 10 is a geometric optical waveguide, the light coupling portion of the geometric optical waveguide is a geometric coupling structure, and the optical engine 30 is opposite to the geometric coupling structure. At this time, the second optical waveguide 20 is a diffractive optical waveguide.
[0074] In one example, the first optical waveguide 10 is a diffractive optical waveguide, the light coupling portion of the diffractive optical waveguide is a one-dimensional grating, and the optical engine 30 is opposite to the light coupling portion of the diffractive optical waveguide. At this time, the second optical waveguide 20 is a geometric optical waveguide.
[0075] The specific implementation manners of the head-mounted display device according to the embodiments of the present application can refer to the embodiments of the above optical transmission device. Therefore, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated one by one here.
[0076] In the above embodiments, the differences between the embodiments are mainly described. As long as the different optimization features between the embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, it will not be elaborated here.
[0077] Although some specific embodiments of the present application have been described in detail by way of examples, those skilled in the art should understand that the above examples are only for illustration and not for limiting the scope of the present application. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.
Claims
1. An optical transmission device, characterized in that, Comprising a first optical waveguide (10) and a second optical waveguide (20) arranged in a stacked manner, in the stacking direction, the light-coupling portions of the first optical waveguide (10) and the second optical waveguide (20) are opposite to each other; The first optical waveguide (10) is configured to couple light in and expand the pupil in at least one dimensional direction and then transmit the light to the second optical waveguide (20); The second optical waveguide (20) is configured to receive the light transmitted by the first optical waveguide (10) and expand the pupil in another dimensional direction and then couple out the light; Wherein, one of the first optical waveguide (10) and the second optical waveguide (20) is a diffractive optical waveguide, and the other is a geometric optical waveguide.
2. The optical transmission device according to claim 1, characterized in that The first optical waveguide (10) and the second optical waveguide (20) are spaced apart in the stacking direction to form a refractive index difference.
3. The optical transmission device according to claim 2, wherein The spacing size between the first optical waveguide (10) and the second optical waveguide (20) is 0.01 mm to 0.1 mm.
4. The optical transmission device according to claim 1, characterized in that, At least one layer is provided for each of the first optical waveguide (10) and the second optical waveguide (20).
5. The optical transmission device according to claim 1, characterized in that The first optical waveguide (10) includes a first light-coupling portion (11) and a first light-coupling-out portion (12); The second optical waveguide (20) includes a second light-coupling portion (21) and a second light-coupling-out portion (22); In the stacking direction, the first light-coupling-out portion (12) is opposite to the second light-coupling portion (21).
6. The optical transmission device according to claim 1, characterized in that, The first optical waveguide (10) is a geometric optical waveguide, and the second optical waveguide (20) is a diffractive optical waveguide.
7. The optical transmission device according to claim 1, characterized in that, The first optical waveguide (10) is a diffractive optical waveguide, and the second optical waveguide (20) is a geometric optical waveguide.
8. The optical transmission device according to any one of claims 1-7, characterized in that, The light-coupling portion of the geometric optical waveguide is a geometric light-coupling structure, and the light-coupling-out portion of the geometric optical waveguide is a diffractive optical structure.
9. The optical transmission device according to claim 8, characterized in that, The geometric light-coupling structure includes a light-coupling prism or a light-coupling inclined surface, and the diffractive optical structure is a one-dimensional grating.
10. The optical transmission device according to any one of claims 1-7, characterized in that, Both the light-coupling portion and the light-coupling-out portion of the diffractive optical waveguide are diffractive optical structures, and their grating vectors and periods are the same.
11. The optical transmission device according to claim 10, characterized in that, The light-coupling portion and the light-coupling-out portion of the diffractive optical waveguide are a single one-dimensional grating or a combination of multiple one-dimensional gratings.
12. The optical transmission device according to claim 10, characterized in that, The light-coupling portion and the light-coupling-out portion of the diffractive optical waveguide form a closed grating vector polygon.
13. A head-mounted display device, characterized in that, Comprising: An optical engine (30); And An optical transmission device according to any one of claims 1-12, wherein the optical engine (30) is opposite to the light-coupling portion of the first optical waveguide (10).