Optical waveguide structure, optical module and smart glasses

Abstract

This application discloses an optical waveguide structure, an optical module, and smart glasses. The optical waveguide structure includes a substrate and a grating disposed on the substrate. The grating includes a first structural layer and a second structural layer. The first structural layer forms multiple mounting spaces, and the second structural layer includes multiple structural components, with each structural component correspondingly mounted within a mounting space. The first and second structural layers are arranged in a volume ratio to form a grating with a preset refractive index. This optical waveguide structure has the advantages of increasing the controllability of the diffraction effect of the optical waveguide structure and reducing grating scattering.

Description

Technical Field

[0001] This application relates to the field of optical waveguide structure technology, and in particular to an optical waveguide structure, an optical module, and smart glasses. Background Technology

[0002] Currently, diffractive waveguides are one of the mainstream technologies for realizing augmented reality. Based on a diffraction grating, an image beam is modulated at a certain angle and coupled into a transparent substrate. Within the substrate, the beam is transmitted losslessly through total internal reflection before being modulated and coupled out to enter the human eye. However, current gratings suffer from limitations in controllability and output quality. Summary of the Invention

[0003] The main purpose of this application is to propose an optical waveguide structure, an optical module, and smart glasses, aiming to at least improve the technical problems of low grating control capability or low output quality.

[0004] To achieve the above objectives, according to some embodiments of this application, this application provides an optical waveguide structure, including a substrate and a grating disposed on the substrate. The grating includes a first structural layer and a second structural layer. The first structural layer forms a plurality of mounting spaces, and the second structural layer includes a plurality of structural components. One of the structural components is correspondingly mounted in one of the mounting spaces. The first structural layer and the second structural layer are arranged in proportion to form the grating having a preset refractive index.

[0005] In some embodiments, the first structural layer includes a plurality of parallel spaced first structural strips, and the plurality of structural members include a plurality of parallel spaced second structural strips. A gap is formed between each pair of adjacent first structural strips, and a second structural strip is disposed in each gap. The first structural strips and the second structural strips are arranged alternately in a volume ratio to form the grating with a preset refractive index.

[0006] In some embodiments, the first structural layer includes at least one of silicon nitride, silicon oxide, titanium oxide, water, or air, and the second structural layer includes at least one of silicon oxide, silicon nitride, titanium oxide, water, or air, wherein the first structural layer and the second structural layer have different compositions.

[0007] In some embodiments, the grating further includes a plurality of third structural strips, wherein the first structural strip and the second structural strip extend along a first direction, the third structural strip extends along a second direction, and the first direction intersects with the second direction.

[0008] In some embodiments, a plurality of first structural strips, a plurality of second structural strips, and a plurality of third structural strips constitute a cross-grid layer, the grating includes a plurality of the cross-grid layers, the plurality of the cross-grid layers are arranged along a third direction, and the first direction, the second direction, and the third direction are arranged perpendicularly to each other;

[0009] The first structural strips of each of the aforementioned intersecting mesh layers are staggered; and / or,

[0010] The second structural strips of each of the aforementioned intersecting grid layers are staggered; and / or,

[0011] The third structural strips of each of the aforementioned intersecting grid layers are misaligned.

[0012] In some embodiments, the grating further includes a plurality of fourth structural strips extending along the second direction, wherein the third structural strips and the fourth structural strips are arranged alternately.

[0013] In some embodiments, a plurality of first structural strips, a plurality of second structural strips, a plurality of third structural strips, and a plurality of fourth structural strips constitute a cross-grid layer, the grating includes a plurality of the cross-grid layers, the plurality of the cross-grid layers are arranged along a third direction, and the first direction, the second direction, and the third direction are arranged perpendicularly to each other;

[0014] The first structural strips of each of the aforementioned intersecting mesh layers are staggered; and / or,

[0015] The second structural strips of each of the aforementioned intersecting grid layers are staggered; and / or,

[0016] The third structural strips of each of the aforementioned intersecting mesh layers are staggered; and / or,

[0017] The fourth structural strips of each of the aforementioned intersecting grid layers are misaligned.

[0018] In some embodiments, the third structural layer includes at least one of silicon nitride, silicon oxide, titanium oxide, water, or air, and the fourth structural layer includes at least one of silicon nitride, silicon oxide, titanium oxide, water, or air, wherein the composition of the fourth structural layer and the third structural layer is different.

[0019] In some embodiments, the plurality of mounting spaces include a plurality of filling holes, and the plurality of structural members include a plurality of mounting units, wherein the number of filling holes is the same as the number of mounting units and is configured in a one-to-one correspondence.

[0020] In some embodiments, the first structural layer and the second structural layer constitute a cyclic layer, and the grating includes a plurality of stacked cyclic layers, wherein at least one of the components, size, shape, position or number of the mounting units in each cyclic layer is different.

[0021] In some embodiments, the first structural layer includes a first part and a second part that are interconnected. The first part is provided with a plurality of first filling holes, and the second part is provided with a plurality of second filling holes. The plurality of structural members include a plurality of first mounting units and a plurality of second mounting units. The number of first filling holes is the same as the number of first mounting units and is provided in a one-to-one correspondence. The number of second filling holes is the same as the number of second mounting units and is provided in a one-to-one correspondence.

[0022] The first mounting unit and the second mounting unit are of different sizes; and / or,

[0023] The first mounting unit and the second mounting unit have different shapes; and / or,

[0024] The number of the first mounting unit and the number of the second mounting unit are different; and / or,

[0025] The first mounting unit and the second mounting unit have different compositions.

[0026] In some embodiments, the first structural layer and the second structural layer constitute a cyclic layer, and the grating includes a plurality of stacked cyclic layers, wherein the first mounting unit and / or the second mounting unit in the cyclic layer are misaligned.

[0027] According to some embodiments of this application, this application provides an optical module including the optical waveguide structure described above, wherein the grating includes an input grating and an output grating, and the optical module further includes an optomechanical system for injecting a light beam into the input grating.

[0028] According to some embodiments of this application, this application provides smart glasses, including the optical module described above.

[0029] In the above scheme, the optical waveguide structure includes a substrate and a grating disposed on the substrate. The grating includes a first structural layer and a second structural layer. The first structural layer forms multiple mounting spaces, and the second structural layer includes multiple structural components, with each structural component correspondingly mounted within a mounting space. The first and second structural layers are arranged in a volume ratio to form a grating with a preset refractive index. This invention has the advantages of increasing the controllability of the diffraction effect of the optical waveguide structure and reducing grating scattering.

[0030] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the optical waveguide structure in some embodiments of this application;

[0033] Figure 2 These are side and top views of optical waveguide structures according to some embodiments of this application;

[0034] Figure 3 This is a side view and a top view of some embodiments of the optical waveguide structure of this application;

[0035] Figure 4 for Figure 3 A schematic diagram of a portion of the grating structure in a waveguide structure;

[0036] Figure 5 This is another side view and a top view of the optical waveguide structure of some embodiments of this application;

[0037] Figure 6 for Figure 5 A schematic diagram of a portion of the grating structure in a waveguide structure;

[0038] Figure 7 Here are another side view and a top view of the optical waveguide structure of some embodiments of this application;

[0039] Figure 8 This is a side view of an optical waveguide structure according to some embodiments of this application;

[0040] Figure 9 This is another side view of the optical waveguide structure of some embodiments of this application;

[0041] Figure 10 for Figure 9 A schematic diagram of a portion of the grating structure in the image;

[0042] Figure 11 for Figure 9 Another schematic diagram of the partial structure of the grating in the image.

[0043] Explanation of icon numbers:

[0044] 100. Optical waveguide structure;

[0045] 1. Substrate; 2. Grating; 21. First structural layer; 211. First structural strip; 22. Second structural layer; 221. Second structural strip; 23. Third structural strip; 24. Fourth structural strip; 25. Cross-grid layer; 26. Circulation layer; 27. First part; 271. First mounting unit; 28. Second part; 281. Second mounting unit; 29. ​​Mounting unit; 201. Coupled-in grating; 202. Turning grating; 203. Coupled-out grating.

[0046] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0047] The technical solutions in this embodiment will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0048] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this embodiment are only used to explain the relative positional relationship and movement of each component in a specific posture (as shown in the attached figure). If the specific posture changes, the directional indicator will also change accordingly.

[0049] Furthermore, the use of terms such as "first," "second," etc., in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0050] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0051] Furthermore, the technical solutions of the various embodiments of this application can be combined with each other, but only if they are feasible to those skilled in the art. If a combination of technical solutions contradicts each other or cannot be implemented, it should be considered that such a combination does not exist and is not within the scope of protection claimed in this application. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0052] The descriptions of directions such as "up", "down", "front", "back", "left", and "right" in this application are based on the directions shown in the figure and are only used to explain the relative positional relationship between the components in the posture shown in the figure. If the specific posture changes, the directional indication will also change accordingly.

[0053] Currently, diffractive waveguides are one of the mainstream technologies for realizing augmented reality. Based on a diffraction grating, an image beam is modulated at a certain angle and coupled into a transparent substrate. Within the substrate, the beam is transmitted losslessly through total internal reflection before being modulated and coupled out to enter the human eye. However, current gratings have limited controllability or suffer from poor output quality.

[0054] After careful research, the applicant discovered that in the related technologies of diffractive waveguides, gratings are usually formed using materials with uniform refractive index (etching medium material, without nanoparticle imprinting adhesive) or near-uniform refractive index (containing nanoparticle imprinting adhesive) to perform the required diffraction modulation on the light beam.

[0055] However, in materials with a uniform refractive index, the refractive index is determined by the material itself, making directional modulation difficult and limited in amplitude, thus restricting the ability to control diffraction effects. In materials with a near-uniform refractive index, refractive index modulation to a certain extent can be achieved by controlling the material, size, and volume ratio of nanoparticles. However, the non-uniformity in size and distribution of the nanoparticles themselves leads to strong scattering, resulting in low transmission quality in optical waveguide performance, specifically including significant loss of light brightness and reduced image sharpness.

[0056] Therefore, this application proposes an optical waveguide structure, an optical module, and smart glasses.

[0057] Reference Figure 1 and Figure 2 According to some embodiments of this application, this application provides an optical waveguide structure 100, including a substrate 1 and a grating 2 disposed on the substrate 1. The grating 2 includes a first structural layer 21 and a second structural layer 22. The first structural layer 21 forms a plurality of mounting spaces, and the second structural layer 22 includes a plurality of structural components. One structural component is correspondingly mounted in a mounting space. The first structural layer 21 and the second structural layer 22 are arranged in proportion to form a grating 2 with a preset refractive index.

[0058] Reference Figure 1 The grating 2 may include an input grating 201, a transition grating 202, and an output grating 203. The light beam typically enters through the input grating 201, undergoes multiple total internal reflections within the substrate 1, and then exits through the output grating 203. In this application's technical solution, the grating 2 includes a first structural layer 21 and a second structural layer 22. The first structural layer 21 and the second structural layer 22 are arranged in a regular pattern, not in a disordered mixed state. Therefore, the volume ratio of the first structural layer 21 and the second structural layer 22 can be controlled during fabrication. Combined with the refractive indices of the materials of the first structural layer 21 and the second structural layer 22, a grating 2 with a preset refractive index can be effectively formed. Conversely, the volume ratio of the first structural layer 21 and the second structural layer 22 can be obtained based on the required refractive index of the grating 2, combined with the refractive indices of the materials of the first structural layer 21 and the second structural layer 22.

[0059] Therefore, compared to existing uniform or approximate refractive index materials, the refractive index of the grating 2 can be adjusted within a wider range by controlling the ratio of the first structural layer 21 and the second structural layer 22, and by using materials with different refractive indices for the first and second structural layers 21 and 22, according to the required refractive index. This results in lower difficulty in directional modulation and a larger adjustment range, increasing the ability to control the diffraction effect. Compared to nanomaterials, the fabrication of the grating 2 in this application allows control over the location of the first and second structural layers 21 and 22, effectively controlling the uniformity of material size and distribution. This reduces scattering by the grating 2, which is beneficial for reducing light energy loss during transmission and improving image sharpness. This embodiment has the advantages of increasing the ability to control the diffraction effect of the optical waveguide structure 100 and reducing scattering by the grating 2.

[0060] Reference Figure 2 In some embodiments, the first structural layer 21 includes multiple parallel and spaced first structural strips 211, and multiple structural components include multiple parallel and spaced second structural strips 221. A gap is formed between each pair of adjacent first structural strips 211, and a second structural strip 221 is provided in each gap. The first structural strips 211 and the second structural strips 221 are arranged alternately in volume ratio to form a grating 2 with a preset refractive index.

[0061] This embodiment describes grating 2 as a one-dimensional structure. Figure 2 Image (a) shows a top view of grating 2. Figure 2 Image (b) shows a side view of grating 2. Figure 2 (a) and Figure 2In (b), the black area represents the first structural strip 211, and the gray area represents the second structural strip 221. The first structural strip 211 and the second structural strip 221 have different compositions. Multiple first structural strips 211 are arranged in parallel and spaced apart, and multiple second structural strips 221 are also arranged in parallel and spaced apart. The second structural strips 221 fill the gaps between two adjacent first structural strips 211. The first structural strips 211 can be obtained by optical manufacturing methods such as coating, exposure, development, and etching. In this way, the position, volume, and weight of the first structural strips 211 can be determined. Then, the second structural strips 221 are set in the gaps. In this way, the position, volume, and weight of the second structural strips 221 can also be determined. Based on the volume of the first structural strips 211 and the second structural strips 221, and the known refractive indices of the first structural strips 211 and the second structural strips 221, the refractive index of the grating 2 can be calculated. This embodiment fabricates the grating 2 by setting alternating first structural strips 211 and second structural strips 221. The desired preset refractive index of the grating 2 can be obtained by controlling the volume ratio of the first structural strips 211 and second structural strips 221. For example, a grating 2 with a refractive index of 1.5, 1.7, or 1.9, or a refractive index less than 1.3, or a refractive index greater than 2.0, can be obtained. This provides greater diffraction modulation capability of the grating 2 and is easy to fabricate. It should be noted that... Figure 2 In section (b), the first structural strip 211 and the second structural strip 221 can be set at an angle, or they can be set horizontally or vertically.

[0062] Specifically, the refractive index of the first structural strip 211 is defined as n1, and its volume fraction as DC1; the refractive index of the second structural strip 221 is defined as n2, and its volume fraction as DC2. Then, the refractive index N of the grating 2 formed by the combination of the first structural strip 211 and the second structural strip 221 is: N = n1DC1 + n2DC2, where n1 + n2 = 1. Those skilled in the art will understand that if the grating 2 is composed of more than two components, then the refractive index N is N = n1DC1 + n2DC2 + ... + niDCi, where ni and DCi are the refractive index and volume fraction of the specified components, respectively, and DC1 + DC2 + ... + DCi = 1. It should also be noted that the method of calculating the refractive index applies to cases where the grating 2 is a two-dimensional or three-dimensional structure. Furthermore, the cell size P in the first structural strip 211 and the second structural strip 221 satisfies: , where n represents the refractive index of substrate 1, λ is the working wavelength, and θ is the propagation angle of light in substrate 1, also known as the working angle or incident angle.

[0063] In some embodiments, the first structural layer 21 comprises at least one of silicon nitride, silicon oxide, titanium oxide, water, or air, and the second structural layer 22 comprises at least one of silicon oxide, silicon nitride, titanium oxide, water, or air. The compositions of the first structural layer 21 and the second structural layer 22 are different. The refractive index of silicon oxide is between 1.44 and 1.55, the refractive index of silicon nitride is between 1.98 and 2.10, and the refractive index of TiO2 is between 2.4 and 2.5. The variation in these refractive indices is due to different crystal forms; for oxides with known crystal forms, their refractive indices are fixed. Furthermore, the refractive index of air is generally 1, and the refractive index of water is generally 1.3. The combination of the first structural layer 21 and the second structural layer 22 can take many forms. Three examples are given below. Those skilled in the art will understand that the scope of protection sought by this application includes, but is not limited to, the following three. In a first embodiment, the first structural layer 21 may be titanium oxide, and the second structural layer 22 may be silicon oxide. Low-refractive-index silicon oxide can serve as a mechanical support and a low-loss substrate, while high-refractive-index titanium oxide enables efficient phase modulation. This combination offers the advantages of mechanical strength, low loss, and efficient modulation. In a second embodiment, the first structural layer 21 can be made of silicon nitride or titanium oxide, and the second structural layer 22 can be made of water. Specifically, the SiN or TiO nanoantenna array can be immersed in an aqueous solution within a microfluidic channel. By changing the water temperature or solution concentration, the refractive index of the environment is altered, thereby dynamically changing the resonant wavelength or phase response of the nanoantenna. In a third embodiment, the first structural layer 21 can be made of silicon oxide, and the second structural layer 22 can be made of air. A key advantage of using air is its low manufacturing cost. This embodiment can achieve a wide range of refractive indices for the grating 2 by selecting first and second structural layers 21 with different compositions and volume ratios.

[0064] Reference Figure 3 and Figure 4 In some embodiments, the grating 2 further includes a plurality of third structural strips 23, wherein the first structural strip 211 and the second structural strip 221 extend along a first direction, and the third structural strips 23 extend along a second direction, with the first and second directions intersecting. This embodiment describes the grating 2 as a two-dimensional structure. Figure 3 Image (e) shows a top view of grating 2. Figure 3 Image (f) shows a side view of grating 2. Figure 4 A schematic diagram of part of the grating 2 is shown. In this embodiment, the first direction is as follows: Figure 3 As shown by the middle arrow X, the second direction is as follows: Figure 3As indicated by the middle arrow Y. The third structural strip 23 is intersecting with the first structural strip 211 and the second structural strip 221. Specifically, the first structural strip 211 and the second structural strip 221 can be arranged parallel to each other, and the third structural strip 23 is arranged perpendicular to the first structural strip 211 and the second structural strip 221. The composition of the third structural strip 23 can be different from that of the first structural strip 211, or the composition of the third structural strip 23 can be different from that of the second structural strip 221. Of course, the composition of the third structural strip 23 can also be different from both the first structural strip 211 and the second structural strip 221. In this case, the grating 2 is arranged in a two-dimensional periodic pattern, and the refractive index N of the grating 2 formed by the combination is: N = n1DC1 + n2DC2 + n3DC3. By using three different structural strips to make the grating 2, it is possible to obtain a grating 2 structure with a preset refractive index, and the scattering phenomenon can be further reduced.

[0065] Reference Figure 4 and Figure 7 In some embodiments, a plurality of first structural strips 211, a plurality of second structural strips 221 and a plurality of third structural strips 23 constitute a cross grid layer 25. The grating 2 includes a plurality of cross grid layers 25, which are arranged along a third direction, with the first direction, the second direction and the third direction being perpendicular to each other.

[0066] The first structural strips 211 of each intersecting grid layer 25 are staggered; and / or,

[0067] The second structural strips 221 of each intersecting grid layer 25 are staggered; and / or,

[0068] The third structural strip 23 of each intersecting grid layer 25 is misaligned.

[0069] This embodiment describes a three-dimensional structure for the grating 2, with the third direction perpendicular to the plane of the paper. This three-dimensional structure is essentially a two-dimensional structure with an added offset, resulting in less scattering. For ease of description, the two-dimensional structure consisting of the first structural strip 211, multiple second structural strips 221, and multiple third structural strips 23 is defined as a cross-grid layer 25. The grating 2 includes multiple cross-grid layers 25 offset along the third direction. This offset can be the offset of the first structural strips 211, the offset of the second structural strips 221, or the offset of the third structural strips 23 of each cross-grid layer 25. Of course, those skilled in the art will understand that any two of the first structural strips 211, the second structural strips 221, and the third structural strips 23, or all of them, can be offset. Using a three-dimensional arrangement is more conducive to reducing light scattering and minimizing the impact on image brightness and quality during transmission.

[0070] Reference Figure 5 and Figure 6 In some embodiments, the grating 2 further includes a plurality of fourth structural strips 24, which extend along the second direction, and the third structural strips 23 and the fourth structural strips 24 are arranged alternately.

[0071] The components of the fourth structural strip 24 may be the same as those of the first structural strip 211 or the second structural strip 221, or they may be different from each other. Of course, it is generally made of a different material than the third structural strip 23. If they are the same, there is no need to describe them separately. The extension direction of the third structural strip 23 is the same as that of the fourth structural strip 24, and the third structural strip 23 and the fourth structural strip 24 are alternately arranged.

[0072] This embodiment describes grating 2 as a two-dimensional structure. Figure 5 Image (c) shows a top view of grating 2. Figure 5 Image (d) shows a side view of grating 2. Figure 6 The diagram shows a partial side view of grating 2. In this embodiment, the first direction is as follows: Figure 5 or Figure 6 As shown by the middle arrow X, the second direction is as follows: Figure 5 or Figure 6As indicated by the middle arrow Y. The third structural strip 23 and the fourth structural strip 24 are arranged alternately, and are generally parallel. The third structural strip 23 intersects with the first structural strip 211 and the second structural strip 221, respectively, and the fourth structural strip 24 intersects with the first structural strip 211 and the second structural strip 221, respectively. Specifically, the first structural strip 211 and the second structural strip 221 can be parallel, the third structural strip 23 is perpendicular to the first structural strip 211 and the second structural strip 221, respectively, and the fourth structural strip 24 is perpendicular to the first structural strip 211 and the second structural strip 221, respectively. The components of the fourth structural strip 24 can be the same as those of the first structural strip 211, or the components of the fourth structural strip 24 can be different from those of the second structural strip 221. Of course, the components of the fourth structural strip 24 are different from those of the first structural strip 211 and the second structural strip 221. In this case, the grating 2 is set in a three-dimensional periodic configuration, and the refractive index N of the grating 2 formed by the combination is: N = n1DC1 + n2DC2 + n3DC3 + n4DC4. By using four structural strips to create the three-dimensional periodic structure of the grating 2, it is possible to obtain a grating 2 structure with a preset refractive index, and further reduce scattering phenomena.

[0073] Reference Figure 6 and Figure 7 In some embodiments, a plurality of first structural strips 211, a plurality of second structural strips 221, a plurality of third structural strips 23 and a plurality of fourth structural strips 24 constitute a cross grid layer 25. The grating 2 includes a plurality of cross grid layers 25, which are arranged along a third direction, with the first direction, the second direction and the third direction being perpendicular to each other.

[0074] The first structural strips 211 of each intersecting grid layer 25 are staggered; and / or,

[0075] The second structural strips 221 of each intersecting grid layer 25 are staggered; and / or,

[0076] The third structural strips 23 of each intersecting grid layer 25 are staggered; and / or,

[0077] The fourth structural strip 24 of each intersecting grid layer 25 is misaligned.

[0078] This embodiment describes the three-dimensional structure of the grating 2, where the third direction is perpendicular to the plane of the paper. The three-dimensional structure is essentially a two-dimensional structure with an added offset setting; if it were perfectly aligned, it would resemble a two-dimensional structure. For ease of description, the two-dimensional structure composed of the first structural strip 211, multiple second structural strips 221, multiple third structural strips 23, and multiple fourth structural strips 24 is defined as a cross-grid layer 25. The grating 2 includes multiple cross-grid layers 25 offset along the third direction. This offset setting can be an offset of the first structural strip 211 of each cross-grid layer 25, an offset of the second structural strip 221 of each cross-grid layer 25, an offset of the third structural strip 23 of each cross-grid layer 25, or an offset of the fourth structural strip 24 of each cross-grid layer 25. Of course, those skilled in the art will understand that it could also be any two or any three of the first structural strip 211, the second structural strip 221, the third structural strip 23, and the fourth structural strip 24, or the first structural strip 211, the second structural strip 221, the third structural strip 23, and the fourth structural strip 24 could all be staggered. Adopting a three-dimensional structural arrangement is more conducive to reducing light scattering and minimizing the impact on image brightness and quality during transmission.

[0079] In some embodiments, the third structural layer includes at least one of silicon nitride, silicon oxide, titanium oxide, water, or air, and the fourth structural layer includes at least one of silicon nitride, silicon oxide, titanium oxide, water, or air, wherein the components of the fourth structural layer and the third structural layer are different.

[0080] As mentioned above, the refractive index of silicon oxide is between 1.44 and 1.55, that of silicon nitride is between 1.98 and 2.10, and that of TiO2 is between 2.4 and 2.5. The variation in these refractive index ranges is due to different crystal forms; for oxides with known crystal forms, their refractive indices are fixed. Furthermore, the refractive index of air is generally 1, and that of water is generally 1.3. Specifically, the combination of the third and fourth structural layers can take many forms; three examples are given below. Those skilled in the art will understand that the scope of protection sought in this application includes, but is not limited to, the following three. In the first embodiment, the third structural layer can be titanium oxide, and the fourth structural layer can be silicon oxide. Low-refractive-index silicon oxide can serve as a mechanical support and a low-loss substrate, while high-refractive-index titanium oxide enables efficient phase modulation. This combination combines the advantages of mechanical strength, low loss, and efficient modulation. In the second embodiment, the third structural layer can be silicon nitride or titanium oxide, and the fourth structural layer can be water. Specifically, SiN or TiO nanoantenna arrays can be immersed in an aqueous solution within a microfluidic channel. By changing the water temperature or solution concentration, the refractive index of the environment is altered, thereby dynamically changing the resonant wavelength or phase response of the nanoantenna. In the third embodiment, the third structural layer can be made of silicon oxide, and the fourth structural layer can be made of air. A key advantage of using air is its low manufacturing cost. This embodiment can achieve a wide range of refractive indices for the grating 2 by selecting different components and volume ratios.

[0081] Reference Figure 8 In some embodiments, the multiple mounting spaces include multiple filling holes, and the multiple structural components include multiple mounting units 29. The number of filling holes is the same as the number of mounting units 29 and they are set in a one-to-one correspondence.

[0082] The foregoing description describes an embodiment where both the first structural layer 21 and the second structural layer 22 are strip-shaped. In this embodiment, the first structural layer 21 constitutes a main structure. Viewed from a cross-section along the XY plane (i.e., a vertical cross-section), the first structural layer 21 has multiple filling holes, and each filling hole contains a mounting unit 29. The filling holes are hollow, while the mounting units 29 are solid. In this embodiment, the first structural layer 21 with multiple filling holes can be fabricated first through coating, exposure, development, and etching. Then, the filling holes are filled with components to form the second structural layer 22. Regarding the materials of the first and second structural layers 21 and 22, the first structural layer 21 can include at least one of silicon nitride, silicon oxide, titanium oxide, water, or air, and the second structural layer 22 can include at least one of silicon oxide, silicon nitride, titanium oxide, water, or air. The compositions of the first and second structural layers 21 are different. Figure 8 In the diagram, the black structure represents the mounting unit 29, and the gray structure represents the first structural layer 21.

[0083] In some embodiments, the first structural layer 21 and the second structural layer 22 form a loop layer 26, and the grating 2 includes a plurality of stacked loop layers 26, wherein at least one of the components, size, shape, position or number of each mounting unit 29 in each loop layer 26 is different.

[0084] The first structural layer 21 and the second structural layer 22 constitute a two-dimensional structure. The loop layer 26 is also a two-dimensional structural layer, and multiple loop layers 26 can be stacked. In this embodiment, the multiple loop layers 26 are staggered. If the loop layer 26 is located in the XY plane, then the stacking direction of the loop layer 26 is the Z direction, which refers to the third direction, i.e. Figure 8 In the direction perpendicular to the paper, the staggered arrangement means that at least one of the components, size, shape, position, or number of each mounting unit 29 is different, thereby forming a periodically arranged three-dimensional structure. The three-dimensional structure scatters less light, which is beneficial to improving image brightness and reducing light energy loss. This embodiment describes that the arrangement of the cyclic layer 26 is not the same in different spaces along the Z-direction of the grating 2, or in other words, on different interfaces.

[0085] Reference Figure 9 and Figure 10 In some embodiments, the first structural layer 21 includes a first portion 27 and a second portion 28 that are interconnected. The first portion 27 is provided with a plurality of first filling holes, and the second portion 28 is provided with a plurality of second filling holes. The plurality of structural components include a plurality of first mounting units 271 and a plurality of second mounting units 281. The number of first filling holes is the same as the number of first mounting units 271 and they are arranged in a one-to-one correspondence. The number of second filling holes is the same as the number of second mounting units 281 and they are arranged in a one-to-one correspondence. The first mounting units 271 and the second mounting units 281 are different in size. And / or, the first mounting units 271 and the second mounting units 281 are different in shape. And / or, the number of first mounting units 271 and the second mounting units 281 is different. And / or, the composition of the first mounting units 271 and the second mounting units 281 is different.

[0086] Figure 9 and Figure 10In the diagram, the black structure represents mounting unit 29, which includes a first mounting unit 271 and a second mounting unit 281. The gray areas represent the first portion 27 and the second portion 28. This embodiment describes a grating 2 in the XY plane composed of two parts with different refractive indices, namely the first portion 27 and the second portion 28. Specifically, the size, shape, number, or composition of the first mounting unit 271 of the first portion 27 and the second mounting unit 281 of the second portion 28 can be different, or any two of them can be different, or any three of them can be different, or all of them can be different. This forms the grating 2 with two parts with different refractive indices, and the desired refractive index can be adjusted as needed.

[0087] In some embodiments, the first structural layer 21 and the second structural layer 22 constitute a loop layer 26, and the grating 2 includes a plurality of stacked loop layers 26, wherein the first mounting unit 271 and / or the second mounting unit 281 in the loop layer 26 are misaligned.

[0088] Following the previous embodiment, the grating 2 not only has two parts with different refractive indices on the cross-section of the XY plane, but can also be staggered in the Z direction, where Z refers to the third direction, that is... Figure 9 In the direction perpendicular to the paper, a grating 2 structure is formed that changes periodically in a three-dimensional structure. The three-dimensional structure scatters less light, which helps to improve image brightness and reduce light energy loss.

[0089] In some embodiments, the grating 2 further includes at least one of nanoparticle material, imprinting adhesive, and etching ring material. The material used to fabricate the grating 2, in addition to the aforementioned silicon nitride, silicon oxide, titanium oxide, water, or air, can also be combined with at least one of existing nanoparticle material, imprinting adhesive, and etching ring material.

[0090] In some embodiments, the number of times the first structural strip 211, the second structural strip 221, the third structural strip 23, or the fourth structural strip 24 repeats periodically in the above-mentioned one-dimensional, two-dimensional, or three-dimensional structures can be set according to actual needs, such as 3 times, 5 times, or more than 10 times, etc. This application introduces a new grating 2 structure, hereinafter referred to as a superstructure layer, which can equivalently form a material with a preset refractive index and a grating 2 structure, thus providing greater grating 2 diffraction modulation capability. Simultaneously, the superstructure layer itself has low or no scattering, ensuring that the brightness and quality of the waveguide image are not affected. This superstructure layer can be used alone as the main body of the grating 2 structure; it can also be used in combination with conventional uniform or near-uniform refractive index materials.

[0091] According to some embodiments of this application, this application provides an optical module including the optical waveguide structure 100 described above. The grating 2 includes an input grating 201 and an output grating 203. The optical module also includes an optomechanical system for injecting a light beam into the input grating 201. Since the optical module includes all the technical solutions of any of the above embodiments, it possesses at least all the beneficial effects brought by all the above technical solutions, which will not be elaborated further here.

[0092] According to some embodiments of this application, this application provides smart glasses, including the optical module described above. The smart glasses can be AR glasses (AR, short for Augmented Reality). Augmented Reality glasses are optical displays composed of microdisplays and optical elements. Without affecting the user's observation of the external environment, they project images generated by the microdisplay onto the user's eyes, achieving the superposition and fusion of the real world and virtual images. They have great application prospects in education, entertainment, industry, and other fields. Currently, optical waveguides are one of the mainstream technical solutions for realizing augmented reality. Since smart glasses include all the technical solutions of any of the above embodiments, they possess at least all the beneficial effects brought by all the above technical solutions, which will not be elaborated further here.

[0093] The above description is merely an optional embodiment of this application and does not limit the scope of protection of this application. Any equivalent structural transformations made based on the content of this application's specification and drawings under the concept of this application, or direct / indirect applications in other related technical fields, are included within the scope of patent protection of this application.

Claims

1. An optical waveguide structure, characterized by, The grating includes a substrate and a grating arranged on the substrate, the grating includes a first structure layer and a second structure layer, the first structure layer is formed with a plurality of mounting spaces, the second structure layer includes a plurality of structure pieces, one structure piece is arranged in one mounting space, and the first structure layer and the second structure layer are arranged in proportion to the volume to form the grating with a preset refractive index. The first structure layer comprises a plurality of first structure strips arranged in parallel and at intervals, and the plurality of structure members comprise a plurality of second structure strips arranged in parallel and at intervals. Adjacent two first structure strips form a gap, and each gap is provided with a second structure strip. The first structure strips and the second structure strips are arranged in volume proportion alternately to form the optical grating with a preset refractive index. The size P of the unit cell in the first structure strips and the second structure strips satisfies: ; Wherein, n represents the refractive index of the substrate, λ is the working wavelength, and θ is the propagation angle of light in the substrate. The grating is composed of two or more components, and the refractive index calculation formula of the grating is: N=n1DC1+n2DC2+...niDCi, Wherein, ni and DCi are the refractive index and volume proportion of the specified component respectively, i is the type of component, and DC1+DC2+...DCi=1.

2. The optical waveguide structure of claim 1, wherein, The first structure layer includes at least one of silicon nitride, silicon oxide, titanium oxide, water or air, the second structure layer includes at least one of silicon oxide, silicon nitride, titanium oxide, water or air, and the composition of the first structure layer and the second structure layer is different.

3. The optical waveguide structure of claim 2, wherein, The grating further includes a plurality of third structure strips, the first structure strips and the second structure strips are arranged along a first direction respectively, and the third structure strips are arranged along a second direction.

4. The optical waveguide structure of claim 3, wherein, The first structure strips, the second structure strips and the third structure strips constitute a cross grid layer, the grating includes a plurality of cross grid layers, and the cross grid layers are arranged along a third direction. The first structure strips of each cross grid layer are arranged in a staggered manner; and / or, The second structure strips of each cross grid layer are arranged in a staggered manner; and / or, The third structure strips of each cross grid layer are arranged in a staggered manner.

5. The optical waveguide structure of claim 3, wherein, The grating further includes a plurality of fourth structure strips, the fourth structure strips are arranged along the second direction, and the third structure strips and the fourth structure strips are arranged alternately.

6. The optical waveguide structure of claim 5, wherein, The first structure strips, the second structure strips, the third structure strips and the fourth structure strips constitute a cross grid layer, the grating includes a plurality of cross grid layers, and the cross grid layers are arranged along a third direction. The first structure strips of each cross grid layer are arranged in a staggered manner; and / or, The second structure strips of each cross grid layer are arranged in a staggered manner; and / or, The third structure strips of each cross grid layer are arranged in a staggered manner; and / or, The fourth structure strips of each cross grid layer are arranged in a staggered manner.

7. The optical waveguide structure of claim 5, wherein, The third structure layer includes at least one of silicon nitride, silicon oxide, titanium oxide, water or air, the fourth structure layer includes at least one of silicon nitride, silicon oxide, titanium oxide, water or air, and the composition of the fourth structure layer and the third structure layer is different.

8. An optical waveguide structure, characterized by The grating includes a substrate and a grating arranged on the substrate, the grating includes a first structure layer and a second structure layer, the first structure layer is formed with a plurality of mounting spaces, and the second structure layer includes a plurality of structural members; the plurality of mounting spaces include a plurality of filling holes, and the plurality of structural members include a plurality of mounting units; the number of the filling holes is the same as the number of the mounting units and is arranged one-to-one; The first structure layer and the second structure layer constitute a cycle layer, and the grating includes a plurality of cycle layers arranged in layers, and at least one of the composition, size, shape, position or number of each mounting unit in each cycle layer is different; The first structure layer and the second structure layer are arranged in proportion to the volume to form the grating with a preset refractive index.

9. The optical waveguide structure of claim 8, wherein, The first structure layer includes a first part and a second part connected to each other, the first part is arranged to form a plurality of first filling holes, and the second part is arranged with a plurality of second filling holes; the plurality of structural members include a plurality of first mounting units and a plurality of second mounting units; the number of the first filling holes is the same as the number of the first mounting units and is arranged one-to-one; and the number of the second filling holes is the same as the number of the second mounting units and is arranged one-to-one. The first mounting unit and the second mounting unit are different in size; and / or, The first mounting unit and the second mounting unit are different in shape; and / or, The first mounting unit and the second mounting unit are different in number; and / or, The first mounting unit and the second mounting unit are different in composition.

10. The optical waveguide structure of claim 9, wherein, The first structure layer and the second structure layer constitute a cycle layer, and the grating includes a plurality of cycle layers arranged in layers, and the first mounting unit and / or the second mounting unit in the cycle layer is arranged in a staggered manner.

11. An optical module characterized by comprising: The optical module includes the optical waveguide structure according to any one of claims 1 to 10, the grating includes a coupling-in grating and a coupling-out grating, and the optical module further includes an optical machine, the optical machine is used for inputting a light beam to the coupling-in grating.

12. A smart glass, characterized by The optical module includes the optical module according to claim 11.

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