Optical waveguide structure

Abstract

The present invention provides an optical waveguide structure. The optical waveguide structure includes: an optical waveguide sheet; a plurality of coupling gratings, which are arranged on the optical waveguide sheet, and the coupling gratings couple the light emitted from an external image source into the optical waveguide sheet; a turning grating, which is used to receive the light from the coupling gratings, and the plurality of coupling gratings are arranged at intervals along the circumferential direction of the turning grating; a coupling-out grating, which is used to receive the light from the turning grating; and a plurality of detectors, which are respectively located on one side of the plurality of coupling gratings away from the turning grating to receive the light that does not enter the turning grating in the coupling gratings. The present invention solves the problem that it is difficult to achieve real-time detection in the existing optical waveguide structure.

Description

Technical Field

[0001] The present invention relates to the technical field of diffractive optical devices, and in particular, to an optical waveguide structure. Background Art

[0002] With the continuous innovation of future technologies, virtual reality (VR), augmented reality (AR), and mixed reality (MR) have gradually entered industries such as industry and education. Among them, in the aspect of AR augmented reality, optical waveguide technology is an indispensable part. In order to achieve better display effects, various complex design splicing schemes have emerged. However, it is a major problem to perform real-time detection on the images of the optical engine. Once there is a splicing deviation in the optical engine images, it will greatly affect the user experience.

[0003] That is to say, the existing optical waveguide structures have the problem that it is difficult to achieve real-time detection. Summary of the Invention

[0004] The main object of the present invention is to provide an optical waveguide structure to solve the problem that it is difficult to achieve real-time detection in the existing optical waveguide structures.

[0005] To achieve the above object, according to one aspect of the present invention, there is provided an optical waveguide structure, including: an optical waveguide sheet; a plurality of coupling gratings disposed on the optical waveguide sheet, and the coupling gratings couple the light emitted from an external image source into the optical waveguide sheet; a turning grating for receiving the light of the coupling gratings, and the plurality of coupling gratings are circumferentially spaced apart around the turning grating; an output grating for receiving the light of the turning grating; a plurality of detectors located on the side of the plurality of coupling gratings away from the turning grating respectively, for receiving the light that does not enter the turning grating in the coupling gratings.

[0006] Further, the detectors are spaced apart from the optical waveguide sheet, and the optical waveguide structure further includes a plurality of slit gratings disposed on the optical waveguide sheet, the slit gratings are provided in one-to-one correspondence with the detectors, and the slit gratings are located in the light incident direction of the detectors.

[0007] Further, the detectors are located on the light incident side of the optical waveguide sheet.

[0008] Further, the detectors are disposed on the optical waveguide sheet and two detectors are respectively located on two opposite sides of the optical waveguide sheet.

[0009] Further, the coupling gratings, the turning grating, and the output grating are all located on the same side of the optical waveguide sheet; or the coupling gratings and the turning grating are located on the same side of the optical waveguide sheet, and the output grating and the turning grating are located on two opposite sides of the optical waveguide sheet.

[0010] Further, when the output grating and the turning grating are located on two opposite sides of the optical waveguide sheet, the turning grating is a two-dimensional grating and the output grating is a one-dimensional grating.

[0011] Further, the input grating is a diffraction grating.

[0012] Further, the period of the diffraction grating is greater than or equal to 300 nanometers and less than or equal to 600 nanometers.

[0013] Further, the material of the optical waveguide sheet is glass; and / or the thickness of the optical waveguide sheet is greater than or equal to 400 micrometers and less than or equal to 1 millimeter; and / or the output grating is one of a blazed grating, an inclined grating, and a rectangular grating; and / or the detector is a CMOS detector.

[0014] Further, there are two input gratings, and the two input gratings are respectively located on two opposite sides of the turning grating. The line connecting the centers of the two input gratings and the center of the turning grating is perpendicular to the line connecting the center of the output grating and the center of the turning grating. The output grating couples out light from the optical waveguide sheet.

[0015] Applying the technical solution of the present invention, the optical waveguide structure includes an optical waveguide sheet, a plurality of input gratings, a turning grating, an output grating, and a detector. The input gratings are arranged on the optical waveguide sheet, and the input gratings couple the light emitted by an external image source into the optical waveguide sheet; the turning grating is used to receive the light from the input gratings, and the plurality of input gratings are arranged at intervals in the circumferential direction around the turning grating; the output grating is used to receive the light from the turning grating; there are a plurality of detectors, and the plurality of detectors are respectively located on one side of the plurality of input gratings away from the turning grating to receive the light that has not entered the turning grating in the input gratings.

[0016] By arranging the input gratings on the optical waveguide sheet, most of the light emitted by the external image source can be coupled into the optical waveguide sheet, ensuring the coupling efficiency of the optical waveguide sheet. The arrangement of the plurality of input gratings can couple the light emitted by the external image source into the optical waveguide sheet from two directions, which is beneficial to improving the output efficiency of the optical waveguide structure. The turning grating is located on one side of the input gratings, and such an arrangement enables most of the light from the input gratings to be incident into the turning grating for the turning grating to amplify the light, ensuring the stable operation of the turning grating. The plurality of detectors are arranged on one side of the plurality of input gratings away from the turning grating, enabling the detectors to utilize the light that has not been coupled into the turning grating. By analyzing the position and intensity of the light intensity signal received by the detectors and comparing it with the originally set standard value, it is determined whether the images of the plurality of external image sources are synchronized and whether there is an offset. Once an abnormality is found, the imaging can be calibrated in real time by adjusting the position of the external image source. The present application provides a convenient calibration method to ensure the accuracy of the output images of the two image sources. Description of the Drawings

[0017] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 shows a schematic structural diagram of the optical waveguide structure of Embodiment 1 of the present invention; and

[0019] Figure 2 shows a schematic structural diagram of the optical waveguide structure of Embodiment 2 of the present invention;

[0020] Figure 3 shows a schematic structural diagram of the optical waveguide structure of Embodiment 3 of the present invention;

[0021] Figure 4 shows Figure 3 [[ID=1�]]a front structural diagram of the optical waveguide sheet in

[0022] Figure 5 shows Figure 3 a back structural diagram of the optical waveguide sheet in

[0023] Figure 6 shows Figure 3 a schematic diagram of the propagation path of light in the optical waveguide sheet in

[0024] Among them, the above-mentioned drawings include the following reference numerals:

[0025] 10. Optical waveguide sheet; 20. Coupling grating; 30. Turning grating; 40. Output coupling grating; 50. Detector; 60. Slit grating. Detailed implementation manners

[0026] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0027] It should be pointed out that unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs.

[0028] In the present invention, unless otherwise stated, the orientation terms such as "upper, lower, top, bottom" are usually in the direction shown in the drawings, or in the vertical, perpendicular or gravitational direction of the component itself; similarly, for the convenience of understanding and description, "inner, outer" refers to the inner and outer of the contour of each component itself, but the above orientation terms do not limit the present invention.

[0029] In order to solve the problem that it is difficult to achieve real-time detection in the existing optical waveguide structure, the present invention provides an optical waveguide structure.

[0030] As shown Figures 1 to 6 in the figure, the optical waveguide structure includes an optical waveguide sheet 10, a plurality of coupling gratings 20, a turning grating 30, an output coupling grating 40, and a detector 50. The coupling grating 20 is disposed on the optical waveguide sheet 10, and the coupling grating 20 couples the light emitted from an external image source into the optical waveguide sheet 10. The turning grating 30 is configured to receive the light from the coupling grating 20, and the plurality of coupling gratings 20 are arranged at intervals in the circumferential direction around the turning grating 30. The output coupling grating 40 is configured to receive the light from the turning grating 30. The plurality of detectors 50 are respectively located on one side of the plurality of coupling gratings 20 away from the turning grating 30, so as to receive the light that does not enter the turning grating 30 in the coupling grating 20.

[0031] By disposing the coupling grating 20 on the optical waveguide sheet 10, most of the light emitted from the external image source can be coupled into the optical waveguide sheet 10, ensuring the coupling efficiency of the optical waveguide sheet 10. The arrangement of the plurality of coupling gratings 20 can couple the light emitted from the external image source into the optical waveguide sheet 10 from two directions, which is beneficial to improving the output efficiency of the optical waveguide structure. The turning grating 30 is located on one side of the coupling grating 20, and such an arrangement enables most of the light from the coupling grating 20 to be incident into the turning grating 30 for the turning grating 30 to amplify the light, ensuring the stable operation of the turning grating 30. The plurality of detectors 50 are disposed on one side of the plurality of coupling gratings 20 away from the turning grating 30, so that the detectors 50 utilize the light that is not coupled into the turning grating 30. By analyzing the position and intensity of the light intensity signal received by the detectors 50 and comparing it with the originally set standard value, it is determined whether the images of the plurality of external image sources are synchronized and whether there is an offset. By adjusting the position of the external image source for calibration, the present application provides a convenient calibration method to ensure the accuracy of the images output by the two image sources.

[0032] It should be noted that the turning grating 30 and the output coupling grating 40 are both disposed on the optical waveguide sheet 10, so as to facilitate the turning grating 30 to receive the light from the coupling grating 20, and at the same time facilitate the output coupling grating 40 to receive the light from the turning grating 30. The coupling grating 20 couples the light into the optical waveguide sheet, the output coupling grating 40 couples the light in the optical waveguide sheet out to the external environment, and the turning grating 30 couples the light at the coupling grating 20 to the output coupling grating 40.

[0033] Since not all of the light coupled by the coupling grating 20 is coupled into the turning grating 30, a detector 50 is disposed at a position of the coupling grating 20 away from the turning grating 30 to receive the light that is not used for imaging in the coupling grating 20. Then, based on the light that is not used for imaging in the coupling grating 20, it is detected whether the images of the plurality of external image sources are synchronized and whether there is an offset, and it will not affect the imaging of the optical waveguide structure.

[0034] It should be noted that the above-mentioned turning grating 30 and the output grating 40 can be designed separately or integrally. As light propagates in the optical waveguide sheet 10, the optical waveguide sheet 10 expands the received light into at least one dimension, enabling the light to propagate at least in one direction. The above-mentioned detector 50 is used to detect the light field intensity inside the optical waveguide sheet 10, and this intensity affects the image quality finally entering the human field of view. On this basis, a standard reference quantity of the light field intensity can be set. If the detected light field intensity is lower than the reference quantity, the energy can be increased in time at the light source to enhance the light field intensity entering the optical waveguide sheet 10; if the detected value is higher than the reference quantity, the light source can be adjusted to reduce the intensity. In this way, the light field inside the optical waveguide sheet 10 can be detected in real time and compensated and adjusted in time according to the detection results, ensuring the imaging quality of the optical waveguide sheet 10.

[0035] By detecting the light not used for imaging through multiple detectors 50, analyzing the positions and intensities of the light intensity signals on the multiple detectors 50 to determine which position of the grating has abnormal operation, and pre-compensating the image influence caused by this defect through the adjustment of the image source to ensure the imaging quality.

[0036] Embodiment 1

[0037] As Figure 1 shown, the detector 50 and the optical waveguide sheet 10 are arranged at intervals. The optical waveguide structure further includes a plurality of slit gratings 60. The slit gratings 60 are arranged on the optical waveguide sheet 10, and the slit gratings 60 are arranged in one-to-one correspondence with the detectors 50. The slit gratings 60 are located in the light incident direction of the detectors 50. The slit gratings 60 are arranged on the optical waveguide sheet 10, and the slit gratings 60 are arranged in one-to-one correspondence with the detectors 50. The slit gratings 60 are located in the light incident direction of the detectors 50. Such an arrangement enables most of the light that does not enter the turning grating 30 in the coupling grating 20 to enter the slit gratings 60 and be coupled out from the slit gratings 60 to the corresponding detectors 50, facilitating the detector 50 to detect the light field inside the optical waveguide sheet 10 in real time and compensate and adjust in time according to the detection results, ensuring the imaging quality of the optical waveguide sheet 10.

[0038] Specifically, the detector 50 is located on the light incident side of the optical waveguide sheet 10. Since the slit gratings 60 and the coupling grating 20 are on the same side surface of the optical waveguide sheet 10, the light coupled out by the slit gratings 60 can be directed to the light incident side of the optical waveguide sheet 10 to ensure that the detector 50 stably receives the light coupled out by the slit gratings 60.

[0039] In Figure 1 the specific embodiment shown, the coupling grating 20, the turning grating 30, and the output grating 40 are all located on the same side surface of the optical waveguide sheet 10. Such an arrangement enables the light incident side and the light output side of the optical waveguide structure to be on the same side of the optical waveguide sheet 10, facilitating the application of the optical waveguide structure in a small space.

[0040] Specifically, the coupling grating 20 is a diffraction grating. The coupling grating 20 being a diffraction grating ensures that the light emitted by the external image source can undergo total internal reflection within the diffraction grating, enabling most of the light emitted by the external image source to be coupled into the optical waveguide sheet 10 and ensuring the coupling efficiency of the coupling grating 20.

[0041] Specifically, the period of the diffraction grating is greater than or equal to 300 nm and less than or equal to 600 nm. Limiting the period of the diffraction grating within the range of 300 nm to 600 nm ensures that the light emitted by the external image source can undergo total internal reflection within the diffraction grating, enabling most of the light emitted by the external image source to be coupled into the optical waveguide sheet 10 and ensuring the stable operation of the coupling grating 20.

[0042] In addition, the material of the optical waveguide sheet 10 is glass. The optical waveguide sheet 10 being made of glass is conducive to the transmission of light inside the optical waveguide sheet 10 and reduces the production cost of the optical waveguide sheet 10 at the same time. It should be noted that the above glass is high-refractive-index glass, which can effectively increase the field of view angle of the optical waveguide sheet 10 and improve the imaging quality of the optical waveguide sheet 10. Similarly, the optical waveguide sheet 10 with different materials can be selected according to actual needs.

[0043] Optionally, the thickness of the optical waveguide sheet 10 is greater than or equal to 400 μm and less than or equal to 1 mm. If the thickness of the optical waveguide sheet 10 is less than 400 μm, it is not easy to fabricate the optical waveguide sheet 10, increasing the processing difficulty of the optical waveguide sheet 10. At the same time, the optical waveguide sheet 10 is prone to breakage during use, reducing the structural strength of the optical waveguide sheet 10. If the thickness of the optical waveguide sheet 10 is greater than 1 mm, the thickness of the optical waveguide sheet 10 is too large, which is not conducive to the miniaturization of the optical waveguide sheet 10. Limiting the thickness of the optical waveguide sheet 10 within the range of 400 μm to 1 mm ensures the miniaturization of the optical waveguide sheet 10 while ensuring the structural strength of the optical waveguide sheet 10.

[0044] Optionally, the output grating 40 is one of a blazed grating, a tilted grating, and a rectangular grating. The output grating 40 being one of a blazed grating, a tilted grating, and a rectangular grating allows different gratings to be used according to different application requirements. The grating can couple out the light field information and specific parameters can be adjusted to adjust the uniformity of the output light field to meet different application requirements, ensuring that the output grating 40 can couple the imaging light out to the human eye while enhancing the versatility of the optical waveguide sheet 10.

[0045] It should be noted that the above blazed grating is a grating with a grooved surface not parallel to the grating normal, that is, there is a small angle between the two, and it has the blazed characteristics. The sawtooth grating is the most ideal blazed grating, and the cross-section of the sawtooth grating is a sawtooth-shaped structure for diffraction. The above-mentioned tilted grating is a grating with a certain inclination angle between the plane of the grating and the tangential direction of the grating. The above-mentioned rectangular grating is a grating with a rectangular cross-section for diffraction.

[0046] Specifically, the detector 50 is a CMOS detector. The detector 50 being a CMOS detector ensures that the CMOS detector can detect the optical field change in the optical waveguide chip 10 in real time, thereby detecting whether the structure in the grating is normal, so that timely compensation and adjustment can be made, ensuring the imaging quality of the optical waveguide chip 10.

[0047] In Figure 1 In the specific embodiment shown, there are two coupling gratings 20. The two coupling gratings 20 are respectively located on the opposite sides of the turning grating 30. The line connecting the centers of the two coupling gratings 20 and the center of the turning grating 30 is perpendicular to the line connecting the center of the output coupling grating 40 and the center of the turning grating 30. The output coupling grating 40 couples out light from the optical waveguide chip 10. The output coupling grating 40 is located on one side of the turning grating 30, and the line connecting the center of the coupling grating 20 and the center of the turning grating 30 is perpendicular to the line connecting the center of the output coupling grating 40 and the center of the turning grating 30. Such a setting enables most of the effective light in the turning grating 30 to be incident into the output coupling grating 40 for the output coupling grating 40 to couple out the light, ensuring the output coupling efficiency of the optical waveguide chip 10, and further ensuring the imaging quality of the optical waveguide chip 10. The two coupling gratings 20 couple the light emitted by two external image sources onto the turning grating 30 to increase the output coupling efficiency of the optical waveguide structure.

[0048] Embodiment 2

[0049] The difference from Embodiment 1 is the position of the detector 50.

[0050] In Figure 2 In the specific embodiment shown, the detector 50 is arranged on the optical waveguide chip 10 and the two detectors 50 are respectively located on the two opposite side surfaces of the optical waveguide chip 10. There is no slit grating 60 arranged on the optical waveguide chip 10, and the detector 50 is arranged on the optical waveguide chip 10. Such a setting enables the optical waveguide chip 10 and the detector 50 to be integrally formed, facilitating the detector 50 to detect in real time the light that does not shoot towards the turning grating 30 in the coupling grating 20. At the same time, the volume of the optical waveguide structure is reduced, ensuring the miniaturization of the optical waveguide structure.

[0051] In addition, the detectors 50 are arranged on two opposite sides of the optical waveguide sheet 10 so that the two detectors 50 can respectively receive the light that is not coupled into the turning grating 30 in the two coupling gratings 20, to determine whether the images of the two external image sources are synchronized and whether there is an offset.

[0052] Embodiment III

[0053] The difference from Embodiment II is that the structure of the turning grating is different.

[0054] As Figures 3 to 6 , the coupling grating 20 and the turning grating 30 are located on the same side of the optical waveguide sheet 10, and the output coupling grating 40 and the turning grating 30 are located on two opposite sides of the optical waveguide sheet 10. The optical waveguide structure in this embodiment is applicable to the scenario of the external image source and the output direction. The optical waveguide sheet 10 in this embodiment can be used in a larger scenario.

[0055] In Figure 3 In the specific embodiment shown, when the output coupling grating 40 and the turning grating 30 are located on two opposite sides of the optical waveguide sheet 10, the turning grating 30 is a two-dimensional grating and the output coupling grating 40 is a one-dimensional grating. With such a setting and under the structure of the optical waveguide sheet 10 of the same size, the areas of the turning grating 30 and the output coupling grating 40 are larger, and the output efficiency of the optical waveguide structure is higher, greatly increasing the output efficiency of the optical waveguide structure. The turning grating 30 adopts a two-dimensional grating, which can couple the light on the surface on the side where the turning grating 30 is located into the output coupling grating 40, greatly increasing the output efficiency of the optical waveguide structure.

[0056] In Figure 6 In the specific embodiment shown, there are two directions for the transmission of the light coupled from one coupling grating 20 into the turning grating 30, and the two-dimensional grating has a high output efficiency.

[0057] Obviously, the above-described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0058] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0059] It should be noted that the terms "first", "second", etc. in the description, claims and the above-mentioned drawings of this application are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of this application described here can be implemented in an order other than those illustrated or described here.

[0060] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An optical waveguide structure, characterized in that, Comprising: An optical waveguide sheet (10); A plurality of coupling gratings (20), the coupling gratings (20) being disposed on the optical waveguide sheet (10), and the coupling gratings (20) coupling light emitted from an external image source into the optical waveguide sheet (10); A turning grating (30), the turning grating (30) being configured to receive the light of the coupling gratings (20), and a plurality of the coupling gratings (20) being disposed at intervals in the circumferential direction around the turning grating (30); An output coupling grating (40), the output coupling grating (40) being configured to receive the light of the turning grating (30); Detectors (50), the detectors (50) being multiple, and the multiple detectors (50) being respectively located on one side of the multiple coupling gratings (20) away from the turning grating (30) to receive the light in the coupling gratings (20) that does not enter the turning grating (30), and detecting whether the images of the multiple external image sources are synchronized and whether there is an offset according to the light in the coupling gratings (20) that does not enter the turning grating (30).

2. The optical waveguide structure according to claim 1, characterized in that, The detectors (50) are disposed at intervals from the optical waveguide sheet (10), and the optical waveguide structure further includes a plurality of slit gratings (60), the slit gratings (60) being disposed on the optical waveguide sheet (10), the slit gratings (60) being disposed in one-to-one correspondence with the detectors (50), and the slit gratings (60) being located in the light incident direction of the detectors (50).

3. The optical waveguide structure according to claim 2, wherein, The detectors (50) are located on the light incident side of the optical waveguide sheet (10).

4. The optical waveguide structure according to claim 1, characterized in that The detectors (50) are disposed on the optical waveguide sheet (10), and two of the detectors (50) are respectively located on two opposite side surfaces of the optical waveguide sheet (10).

5. The optical waveguide structure according to claim 1, wherein The coupling gratings (20), the turning grating (30), and the output coupling grating (40) are all located on the same side surface of the optical waveguide sheet (10); or The coupling gratings (20) and the turning grating (30) are located on the same side surface of the optical waveguide sheet (10), and the output coupling grating (40) and the turning grating (30) are located on two opposite side surfaces of the optical waveguide sheet (10).

6. The optical waveguide structure according to claim 5, characterized in that When the output coupling grating (40) and the turning grating (30) are located on two opposite side surfaces of the optical waveguide sheet (10), the turning grating (30) is a two-dimensional grating, and the output coupling grating (40) is a one-dimensional grating.

7. The optical waveguide structure according to any one of claims 1 to 6, characterized in that, The coupling gratings (20) are diffraction gratings.

8. The optical waveguide structure according to claim 7, characterized in that, The period of the diffraction grating is greater than or equal to 300 nanometers and less than or equal to 600 nanometers.

9. The optical waveguide structure according to any one of claims 1 to 6, wherein The material of the optical waveguide sheet (10) is glass; and / or The thickness of the optical waveguide sheet (10) is greater than or equal to 400 micrometers and less than or equal to 1 millimeter; The output coupling grating (40) is one of a blazed grating, an inclined grating, and a rectangular grating; and / or [[ID= 10. The optical waveguide structure according to any one of claims 1 to 6, characterized in that, There are two input gratings (20), and the two input gratings (20) are respectively located on opposite sides of the turning grating (30). The line connecting the centers of the two input gratings (20) and the center of the turning grating (30) is perpendicular to the line connecting the center of the output grating (40) and the center of the turning grating (30). The output grating (40) couples the light out of the optical waveguide chip (10).

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