Optical waveguide structure

Abstract

A kind of optical waveguide structure is disclosed, the optical waveguide structure includes substrate.Light waveguide structure also includes on the substrate, incident grating area, turning grating area and exit grating area.Each of incident grating area, turning grating area and exit grating area includes a plurality of periodic arrangement super-photonic grating unit.Each super-photonic grating unit includes first grating and second grating.In this way, electromagnetic wave regulation can be realized by super-photonic grating, and the formation of super-photonic grating can have high tolerance to etching tolerance.

Description

Technical Field

[0001] This invention relates to optical waveguide structures. Background Technology

[0002] Optical waveguide structures can be used, for example, to implement displays in head-mounted display devices. For instance, the optical waveguide structure can be positioned in front of the user's line of sight. The image source of the head-mounted display emits light containing an image toward the optical waveguide structure, and the light propagates the image through the waveguide structure to the front of the user's line of sight. In some embodiments, the structure of the optical waveguide used to modulate the light may include tilted gratings of different depths.

[0003] However, the manufacturing process of tilted gratings is difficult, and tilted gratings are highly sensitive to the depth and angle tolerances of the grating, which can cause stray light problems, such as eye glow or image misalignment. Summary of the Invention

[0004] One aspect of this invention relates to optical waveguide structures.

[0005] According to one or more embodiments of the present invention, an optical waveguide structure includes a substrate, an incident grating region, a transition grating region, and an exit grating region. The incident grating region is located on the substrate and includes a plurality of periodically arranged incident metagloss units. The transition grating region is located on the substrate and includes a plurality of periodically arranged transition metagloss units. The incident grating region and the transition grating region are arranged along a first direction. The exit grating region is located on the substrate and includes a plurality of exit grating sections. The exit grating region is located on one side of the transition grating region. The transition grating region and the exit grating region are arranged along a second direction different from the first direction. Each of the incident metagloss unit, the transition metagloss unit, and the exit metagloss unit includes a first grating and a second grating. In the period length of each of the incident super-gloss grating unit, the folding super-gloss grating unit, and the exiting super-gloss grating unit, the first grating has a first shape in a cross-section, the second grating has a second shape in a cross-section, the first shape has a first width on a first boundary of the period length, the second shape has a second width, there is a first gap between the first shape and the second shape, the second shape is separated from a second boundary of the period length by a second gap, the first width is greater than or equal to the second width, and the ratio of the first gap to the second gap is in the range of 0.1 to 10.

[0006] One aspect of this invention relates to optical waveguide structures.

[0007] According to one or more embodiments of the present invention, an optical waveguide structure includes a substrate, an incident grating region located on the substrate and including a plurality of periodically arranged incident metagloss grating units, a transition grating region located on the substrate and including a plurality of periodically arranged transition metagloss grating units, and an exit grating region located on the substrate and including a plurality of exit grating sections. The incident grating region and the transition grating region are arranged along a first direction. The exit grating region is located on one side of the transition grating region. The transition grating region and the exit grating region are arranged along a second direction different from the first direction. Each of the exit grating sections includes a plurality of periodically arranged exit metagloss grating units. Each of the incident metagloss grating unit, the transition metagloss grating unit, and the exit metagloss grating unit includes a first grating and a second grating, and the plurality of top surfaces of the first grating and the second grating of the incident metagloss grating unit, the transition metagloss grating unit, and the exit metagloss grating unit have the same height.

[0008] In summary, waveguide structures with metagratings can modulate electromagnetic wave propagation, achieving diffraction, deflection, and outgoing light. Multiple metagratings at different locations can be formed using the same etching process and can have the same height. Furthermore, using metagratings to modulate electromagnetic waves offers high tolerance to etching tolerances.

[0009] The above description is only used to illustrate the problem to be solved by the present invention, the technical means to solve the problem, and the effects produced, etc. The specific details of the present invention will be described in detail in the following embodiments and related drawings. Attached Figure Description

[0010] The advantages of this invention and the accompanying drawings should be better understood from the embodiments listed below, and with reference to the drawings. These drawings are merely illustrative of embodiments and should not be construed as limiting the specific embodiments or the scope of the claims.

[0011] Figure 1A This is a schematic diagram illustrating the structure of a display device according to one or more embodiments of the present invention;

[0012] Figure 1B A top view of an optical waveguide structure is illustrated as an example of one or more embodiments of the present invention;

[0013] Figure 1C Partial cross-sectional views of the incident grating region, the transition grating region, and the exit grating region on the substrate are shown for one or more embodiments of the present invention.

[0014] Figure 2A A schematic diagram illustrating a super-obvious grating unit in the incident grating region for one or more embodiments of the present invention;

[0015] Figure 2B for Figure 2A The plot shows the relationship between the transmitted or reflected diffracted light and the diffraction efficiency for different incident angles and orders in the incident grating area.

[0016] Figure 3A A schematic diagram illustrating a super-obvious grating unit in the transition grating region for one or more embodiments of the present invention;

[0017] Figure 3B for Figure 3A The diagram illustrates the relationship between the transmitted or reflected diffracted light and the diffraction efficiency for different incident angles and orders of diffraction in the folding grating region.

[0018] Figure 4A A schematic diagram illustrating a super-obvious grating unit in the transition grating region for one or more embodiments of the present invention;

[0019] Figure 4B for Figure 4A The diagram illustrates the relationship between the transmitted or reflected diffracted light and the diffraction efficiency for different incident angles and orders of diffraction in the folding grating region.

[0020] Figure 5A A schematic diagram of the super-obvious grating unit in the reflective grating region is shown for one or more embodiments of the present invention;

[0021] Figure 5B for Figure 5A The diagram illustrates the relationship between the transmitted or reflected diffracted light and the diffraction efficiency for different incident angles and orders of diffraction in the folding grating region.

[0022] Figure 6A A schematic diagram of the super-obvious grating unit in the reflective grating region is shown for one or more embodiments of the present invention;

[0023] Figure 6B for Figure 6A The diagram illustrates the relationship between the transmitted or reflected diffracted light and the diffraction efficiency for different incident angles and orders of diffraction in the folding grating region.

[0024] Figure 7A A schematic diagram of the super-obvious grating unit in the reflective grating region is shown for one or more embodiments of the present invention;

[0025] Figure 7B for Figure 7A The diagram illustrates the relationship between the transmitted or reflected diffracted light and the diffraction efficiency for different incident angles and orders of diffraction in the folding grating region.

[0026] Figure 8A A schematic diagram of the super-obvious grating unit in the reflective grating region is shown for one or more embodiments of the present invention;

[0027] Figure 8B for Figure 8A The diagram illustrates the relationship between the transmitted or reflected diffracted light and the diffraction efficiency for different incident angles and orders of diffraction in the folding grating region.

[0028] Figure 9A A schematic diagram of the super-obvious grating unit in the reflective grating region is shown for one or more embodiments of the present invention;

[0029] Figure 9B for Figure 9A The diagram illustrates the relationship between the transmitted or reflected diffracted light and the diffraction efficiency for different incident angles and orders of diffraction in the folding grating region.

[0030] Figure 10 This is a schematic diagram illustrating the structure of a display device according to one or more embodiments of the present invention;

[0031] Figures 11A to 11E Schematic diagrams of multiple super-highlighted grating units are shown for various embodiments of the present invention;

[0032] Figure 11F for Figures 11A to 11E Cross-sections of multiple super-inspired grating units; and

[0033] Figures 12 to 15 Schematic diagrams of multiple super-gloss grating units are shown for various embodiments of the present invention.

[0034] Symbol Explanation

[0035] 0R,0T,-1T,1T,-1R,1R,2R: Curve

[0036] 100: Display device

[0037] 110: Image Source

[0038] 200,200': Optical waveguide structure

[0039] 210:Substrate

[0040] 221, 222, 223: Raster

[0041] 231, 232, 233: Raster

[0042] 241, 242, 243: Raster

[0043] 251, 252, 253: Raster

[0044] 2521, 2531: First grating section

[0045] 2522, 2532: Second grating section

[0046] C1-C1', C2-C2', C3-C3', C4-C4', C5-C5': line segments

[0047] DA: direction

[0048] FG: Convex raster area

[0049] FG1, FG2: Tilting raster partitions

[0050] FGC, FGC1: Supergrating unit

[0051] FGS: Light-emitting side

[0052] G1, G2: Spacing

[0053] GC, GC1, GC2, GC3, GC4, GC5: Supergraphite raster units

[0054] GC6, GC7, GC8, GC9, GC10: Supergraphite raster units

[0055] H: Height

[0056] IB: Image Box

[0057] IG: Incident grating area

[0058] IGC: Super-Grater Unit

[0059] L0, L1, L2, L3, L4, L5: Light rays

[0060] O: Pupil

[0061] OG: Exit grating area

[0062] OG1, OG2, OG3, OG4, OG5, OGM: Output grating partitions

[0063] OGC, OGC1, OGCM, OGC5: Super-Grater Unit

[0064] TIG: Period Length

[0065] TFG, TFG1: Period length

[0066] TOG, TOG1, TOGM, TOG5: Period length

[0067] TGC: Cycle Length

[0068] W1, W2: Width

[0069] X, Y, Z: Direction

[0070] θ: Angle of incidence Detailed Implementation

[0071] The following is a detailed description of embodiments in conjunction with the accompanying drawings. However, the provided embodiments are not intended to limit the scope of the invention, and the description of the structural operation is not intended to limit the order of execution. Any structure resulting from the recombination of elements, producing a device with equivalent functionality, is within the scope of this invention. Furthermore, the drawings are for illustrative purposes only and are not drawn to their original dimensions. For ease of understanding, the same or similar elements will be designated with the same symbols in the following description.

[0072] Furthermore, unless otherwise specified, the terms used throughout this specification and claims generally have their ordinary meaning in the context of this art, the disclosure herein, and the specific content. Certain terms used to describe the invention will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing the invention.

[0073] In this document, terms such as "first," "second," etc., are used only to distinguish elements or methods of operation that have the same technical terms, and are not intended to indicate order or limit the invention.

[0074] In addition, terms such as "contains," "includes," and "provides" are all open-ended restrictions in this article, meaning that they include but are not limited to.

[0075] Furthermore, in this document, unless otherwise specified in the text, "a" and "the" may refer to one or more in general. It will be further understood that the terms "comprising," "including," "having," and similar words as used herein specify the features, regions, integers, steps, operations, elements, and / or components described herein, but do not exclude one or more other features, regions, integers, steps, operations, elements, components, and / or groups thereof described or additionally described herein.

[0076] This invention relates to an optical waveguide structure with a meta-grating and a display device using the optical waveguide structure. The meta-grating can be a grating structure with a size close to the wavelength of visible light and arranged periodically. In some embodiments, the electromagnetic wave characteristics can be modulated by designing the size of individual grating structures in the meta-grating or by designing the periodicity of the arrangement between grating structures. The meta-grating can be applied, for example, to an augmented reality display device. Image light emitted from the image source of the display device can be coupled to a transparent substrate through the meta-grating, and diffracted, deflected, and emitted through the meta-grating, allowing the user of the display device to view the augmented reality image. In one or more embodiments of this invention, the meta-grating is formed on a substrate, the grating structure of the meta-grating extending vertically upwards from the surface of the substrate, and these grating structures may have the same height relative to the surface of the substrate. In some embodiments, the grating structure of the meta-grating can be formed by etching the same layer of grating material. In one or more embodiments of this invention, the meta-grating has a high tolerance for differences in etching depth.

[0077] Please refer to Figure 1A . Figure 1A A schematic diagram of the structure of a display device 100 is shown according to one or more embodiments of the present invention. For example... Figure 1A As shown, the display device 100 includes an image source 110 and an optical waveguide structure 200. The optical waveguide structure 200 includes a substrate 210. The substrate 210 may be a transparent substrate, and the refractive index of the substrate 210 is such that total internal reflection of electromagnetic waves occurs within the substrate 210. The optical waveguide structure 200 also includes an incident grating region IG, a transition grating region FG, and an exit grating region OG on the substrate 210. In some embodiments, such as Figure 1A As shown, the exit grating region OG may include multiple exit grating partitions OG1, OG2, OG3, OG4, and OG5. In one or more embodiments of the present invention, each of the multiple exit grating partitions OG1, OG2, OG3, OG4, and OG5 of the incident grating region IG, the transition grating region FG, and the exit grating region OG may include multiple super-grating units, which can be used to modulate the image light emitted from the image source 110.

[0078] For ease of explanation, Figure 1A The metagated elements are not shown. For the optical waveguide structure 200, which includes multiple metagated elements, please refer to [reference needed]. Figure 1B . Figure 1B A top view of an optical waveguide structure 200 is illustrated as an example of one or more embodiments of the present invention. Figure 1BMultiple super-grate elements are schematically illustrated in the incident grating region IG, the transition grating region FG, and the exit grating region OG, specifically in the multiple exit grating sections OG1, OG2, OG3, OG4, and OG5. For ease of explanation, Figure 1B The diagram schematically illustrates at least one set of metagated elements from each of the plurality of exit grating sections OG1, OG2, OG3, OG4, and OG5 of the incident grating region IG, the transition grating region FG, and the exit grating region OG. The incident grating region IG includes a plurality of gratings 221. The plurality of gratings 221 may extend parallel to each other in the Y direction. In some embodiments, the plurality of gratings 221 of the incident grating region IG forms a plurality of metagated elements arranged periodically. In some embodiments, such as Figure 1B As shown, the multiple gratings 221 in the incident grating region IG can be arranged along the X direction.

[0079] The transition grating region FG may include a plurality of gratings 231. The plurality of gratings 231 in the transition grating region FG form a plurality of periodically arranged metagloss grating units. In some embodiments, such as Figure 1B As shown, the plurality of gratings 231 in the transition grating region FG may be arranged in a direction different from the X and Y directions. For example, the plurality of gratings 231 in the transition grating region FG may be arranged in a direction on the XY plane that is rotated counterclockwise by 45 degrees from the X direction. The plurality of gratings 231 may extend parallel to each other in a direction perpendicular to the arrangement direction. In some embodiments, the transition grating region FG may include a front transition grating partition FG1, a rear transition grating partition FG2, and one or more intermediate transition grating partitions between the front transition grating partition FG1 and the rear transition grating partition FG2. Each of the front transition grating partition FG1, the rear transition grating partition FG2, and the one or more intermediate transition grating partitions between the front transition grating partition FG1 and the rear transition grating partition FG2 may include periodically arranged metagrating units.

[0080] The multiple exit grating sections OG1, OG2, OG3, OG4, and OG5 of the exit grating region OG include multiple gratings 241. The multiple gratings 241 may extend parallel to each other in the X direction. The multiple gratings 241 of the exit grating sections OG1, OG2, OG3, OG4, and OG5 form a multiple periodically arranged metagated grating units. In some embodiments, such as... Figure 1B As shown, multiple gratings 241 are arranged in the Y direction. In some embodiments, the super-grate units of different exit grating partitions OG1, OG2, OG3, OG4 and OG5 are designed to have different diffraction efficiencies.

[0081] Please refer to the following at the same time Figure 1A and Figure 1BIn one or more embodiments, the optical waveguide structure 200 is capable of two-dimensionally expanding the image light emitted by the image source 110. For example... Figure 1AAs shown, image source 110 is located on optical waveguide structure 200 in the Z direction. Image source 110 emits light ray L0 containing an image towards the incident grating region IG of optical waveguide structure 200 at an incident angle θ. The superstructure grating unit of incident grating region IG is a diffraction grating, which enables light ray L0 to diffract, thereby deflecting light ray L0 into substrate 210. After light ray L0 enters substrate 210 through incident grating region IG, it undergoes +1 order transmission diffraction and is modulated (e.g., through grating 221) into light ray L1. In the X direction, light ray L1 propagates within substrate 210 by total internal reflection into transition grating region FG. The superstructure grating unit of transition grating region FG is a reflection diffraction grating. After entering transition grating region FG, light ray L1 is converted into two-dimensional path diffraction. Light ray L1 enters transition grating region FG and is modulated (e.g., through grating 231) into light ray L2 and light ray L3. Ray L2, for example, is a 0th-order reflective diffracted ray, propagating by total internal reflection along the X-direction of the transition grating region FG. For instance, ray L2 may sequentially pass through the front transition grating section FG1, one or more intermediate transition grating sections between the front and rear transition grating sections FG1 and FG2, and the rear transition grating section FG2. Ray L3, for example, is a -1st-order reflective diffracted ray, propagating in the negative Y-direction within the substrate 210. Ray L3 can exit through the light-emitting side FGS of the transition grating region FG and propagate towards the exit grating region OG. As ray L2 travels within the transition grating region FG, multiple sets of ray L3 will exit from different positions on the X-direction light-emitting side FGS to the exit grating region OG, achieving pupil expansion in the X-direction. The super-grating unit of the exit grating region OG is a through-beam diffraction grating. After entering the exit grating region OG, ray L3 is converted into two-dimensional path diffraction. After entering the exit grating region OG, light ray L3 is modulated (e.g., through grating 241) into light rays L4 and L5. Light ray L4 is, for example, a 0th-order reflective diffracted ray, propagating along the negative Y direction. Light ray L5 is, for example, a +1st-order transmissive diffracted ray, coupled out of the substrate 210 through the exit grating region OG and emitted along the perpendicular Z direction. The exit grating region OG includes multiple exit grating sections OG1, OG2, OG3, OG4, and OG5. Light ray L4 can sequentially pass through exit grating sections OG1, OG2, OG3, OG4, and OG5. The exit grating sections OG1, OG2, OG3, OG4, and OG5 have different diffraction efficiency characteristics for different types and orders of diffracted light. This allows light ray L4 to travel in the negative Y direction, and light ray L5 to exit from different positions in the negative Y direction of the exit grating section OG, thus achieving pupil dilation in the Y direction. In this way, light ray L0 emitted from image source 110, after passing through the incident grating section IG, the deflection grating section FG, and the exit grating section OG, can exit from different positions in the X and Y directions of the exit grating section OG, resulting in light ray L5. The user's pupil O views the display device 100 in the Z direction.The light beam L5 emitted from the optical waveguide structure 200 forms multiple image boxes IB in front of the pupil O. The image beam L0 corresponding to different image boxes IB is imaged at different positions in front of the pupil O after two-dimensional pupil dilation. When the user's pupil O moves, the pupil O receives the images of different image boxes IB.

[0082] Figure 1C Partial cross-sectional views of the incident grating region IG, the transition grating region FG, and the exit grating region OG on the substrate 210 are shown according to one or more embodiments of the present invention. For ease of explanation, Figure 1C Multiple cross-sectional views of grating 221 in the incident grating region IG, grating 231 in the turning grating region FG, and grating 241 in the exit grating region OG are shown in their respective periodic arrangement directions DA.

[0083] For example, refer to Figure 1B and Figure 1C The arrangement direction DA of the gratings 221 in the incident grating region IG can be the X direction, the arrangement direction DA of the gratings 231 in the transition grating region FG can be a direction rotated 45 degrees relative to the X direction, and the arrangement direction DA of the gratings 241 in the exit grating region OG can be the Y direction. A partial cross-sectional view of the incident grating region IG includes an incident metaglossary unit IGC with a period length TIG. The gratings 221 of the incident metaglossary unit IGC include a first grating 222 and a second grating 223 on the substrate 210. The first grating 222 is located on a boundary of the incident metaglossary unit IGC. The second grating 223 is spaced apart from the first grating 222 within the period length TIG. A partial cross-sectional view of the transition grating region FG includes a transition metaglossary unit FGC with a period length TFG. The gratings 231 of the transition metaglossary unit FGC include a first grating 232 and a second grating 233 on the substrate 210. The first grating 232 is located on a boundary of the transition metagated cell FGC. The second grating 233 is spaced apart from the first grating 232 within a period length TFG. A partial cross-sectional view of the emission grating region OG includes an emission metagated cell OGC with a period length TOG. The grating 241 of the emission metagated cell OGC includes the first grating 242 and the second grating 243 on the substrate 210. The first grating 242 is located on a boundary of the emission metagated cell OGC. The second grating 243 is spaced apart from the first grating 242 within a period length TOG.

[0084] Figure 1CThe formation of grating 221 in the incident grating region IG, grating 231 in the transition grating region FG, and grating 241 in the exit grating region OG on a substrate is described. For example, in one or more embodiments of the present invention, a grating material layer can be formed on a substrate 210. The grating material layer can be formed on the substrate 210, for example, by a suitable deposition process. The formation of the grating material layer may also include polishing the grating material layer so that the top surface of the grating material layer is flat. Subsequently, patterning is performed on the grating material layer. Patterning the grating material layer may include forming an etch pattern mask layer on the grating material layer and etching the grating material layer based on the mask layer. Thus, grating 221 in the incident grating region IG, grating 231 in the transition grating region FG, and grating 241 in the exit grating region OG can be defined in the same etching process. Figure 1C As shown, the multiple top surfaces of the formed gratings 221, 231, and 241 may have the same height H relative to the top surface of the substrate 210. In some embodiments, due to the grating pattern design, etching differences may occur in the incident grating region IG, the transition grating region FG, and the exit grating region OG, and the multiple top surfaces of gratings 221, 231, and 241 may individually have different heights H relative to the top surface of the substrate 210. In some embodiments, the height H may be in the range of 200 nm to 500 nm.

[0085] In some embodiments, substrate 210 is a transparent substrate and has a refractive index greater than 1.7 for diffracted light entering substrate 210. In some embodiments, the refractive index of substrate 210 is, for example, 2. In some embodiments, gratings 221, 231, and 241 have a refractive index greater than 1.7 for diffracted light entering gratings 221, 231, and 241. In some embodiments, the refractive index of gratings 221, 231, and 241 is, for example, 2.6. In some embodiments, the material of substrate 210 includes, for example, gallium phosphide (GaP). In some embodiments, the grating material of gratings 221, 231, and 241 includes, for example, silicon oxide or silicon nitride. In some embodiments, the grating material of gratings 221, 231, and 241 includes, for example, gallium nitride (GaN), gallium phosphide (GaP), aluminum arsenide (AlAs), aluminum gallium arsenide (AlGaAs), titanium dioxide (TiO2), silicon (Si), or silicon nitride (Si3N4). In some embodiments, the grating materials of gratings 221, 231 and 241 may be the same as the material of substrate 210.

[0086] Please refer to Figure 2A . Figure 2A The super-grate cell IGC of the incident grating region IG is illustrated according to one or more embodiments of the present invention. Figure 2AIn the process, the first grating 222 is located on the boundary of the metagrating cell IGC. Within the period length TIG of the metagrating cell IGC, the first grating 222 is aligned in the alignment direction DA (e.g., Figure 1B The first grating 222 has a width W1 in the X direction. The first grating 222 is spaced from the second grating 223 by a spacing G1 in the alignment direction DA. The second grating 223 has a width W2 in the alignment direction DA. The second grating 223 is spaced from the boundary of the super-gloss grating cell IGC by a spacing G2 in the alignment direction DA. In some embodiments, such as... Figure 2A As shown, the width W1 is greater than the width W2, and the spacing G1 is greater than the spacing G2. Thus, multiple meta-grating units IGC are arranged periodically in the arrangement direction DA with a period length TIG, forming the incident grating region IG.

[0087] Figure 2B Drawing for Figure 2A The incident grating region IG shown corresponds to different incident angles θ (e.g. Figure 1A The plot shows the relationship between the transmitted or reflected diffracted light of different orders (at the incident angle θ) and the diffraction efficiency. Figure 2B The horizontal axis corresponds to the incident angle θ, in degrees. Figure 2B The vertical axis corresponds to the diffraction efficiency, which is expressed in arbitrary units (au). Figure 2B The curves 0T, 1T, and -1T correspond to the 0th, 1st, and -1st order transmitted diffracted light, respectively. Figure 2B In this process, the diffraction efficiency of the 0th-order transmitted diffracted light is suppressed, reducing RGB misalignment. Within the incident angle range, the diffraction efficiency of the 1T and -1T orders of transmitted diffracted light is greater than that of the 0th-order transmitted diffracted light. The diffraction efficiencies of the 1T and -1T orders of transmitted diffracted light have a larger slope relative to the incident angle range, increasing uniformity. The 1T and -1T orders of transmitted diffracted light have the dominant diffraction efficiency, reducing the mixing of other orders of transmitted diffracted light or reflected diffracted light.

[0088] In some embodiments, in the incident metaglossary cell IGC of the incident grating region IG, the width W1 is greater than the width W2, and the spacing G1 is greater than the spacing G2. In some embodiments, in the incident metaglossary cell IGC of the incident grating region IG, the ratio of the period length TIG to the width W1 is in the range of 2.4 to 2.8, the ratio of the period length TIG to the spacing G1 is in the range of 2.7 to 3.9, the ratio of the width W1 to the width W2 is in the range of 2.7 to 3.8, and the ratio of the spacing G1 to the spacing G2 is in the range of 1.1 to 2.8. In some embodiments, the diffraction efficiency is designed to gradually decrease between -15 degrees and +15 degrees of air incident angle θ.

[0089] Please refer to Figure 3A . Figure 3AThe super-grate unit FGC of the transition grating region FG is illustrated according to one or more embodiments of the present invention. Figure 3A Multiple gratings 231 are drawn. Figure 3A In the process, the first grating 232 is located on the boundary of the metagrating unit FGC. Within the period length TFG of the metagrating unit FGC, the first grating 232 is aligned in the arrangement direction DA (e.g., Figure 1B The grating 231 has a width W1 in its arrangement direction DA. The first grating 232 is spaced apart from the second grating 233 by a spacing G1 in the arrangement direction DA. The second grating 233 has a width W2 in the arrangement direction DA. The second grating 233 is spaced apart from the boundary of the super-grating unit FGC by a spacing G2 in the arrangement direction DA. In some embodiments, such as Figure 3A As shown, the width W1 is approximately equal to the width W2, or the width W1 is directly equal to the width W2, and the spacing G1 is greater than the spacing G2. In this way, multiple super-grate units FGC are arranged periodically with a period length TFG in the arrangement direction DA, forming the transition grating region FG.

[0090] Figure 3B Drawing for Figure 3A The diagram illustrates the relationship between the transmitted or reflected diffracted light of different orders and diffraction efficiency at different incident angles in the grating region FG. Figure 3B The horizontal axis corresponds to the incident angle θ, in degrees. Figure 3B The vertical axis corresponds to the diffraction efficiency, which is expressed in arbitrary units (au). Figure 3B The curves 0R and -1R correspond to the 0th and -1st order reflected diffracted light, respectively. Figure 3B Within the illustrated incident angle range, the diffraction efficiency of the 0th order reflected diffracted light is greater than that of the -1st order reflected diffracted light. The diffraction efficiency of the 0th order reflected diffracted light is greater than that of other orders of reflected diffracted light or transmitted diffracted light, and it has good uniformity.

[0091] Please refer to Figure 4A . Figure 4A The angular grating section FG1 is illustrated according to one or more embodiments of the present invention (e.g., Figure 1B The super-grate unit FGC1 of the front-end transition grate section FG1 is illustrated. Compared to Figure 3A The super-highlighted grating unit FGC in the transition grating region FG, in Figure 4A In the period length TFG1 of the super-grate unit FGC1 of the transition grating partition FG1, the width W1 is greater than the width W2, and the spacing G1 is equal to the spacing G2. Figure 4B Drawing for Figure 4A The diagram illustrates the relationship between the diffraction efficiency and the order of transmitted or reflected diffracted light at different incident angles in the grating region FG. Figure 4BEven so, it can still ensure that within a specific incident angle range, the diffraction efficiency of the 0th-order reflected diffracted light is greater than that of the -1st-order reflected diffracted light, and the diffraction efficiency of the 0th-order reflected diffracted light is greater than that of other orders of reflected or transmitted diffracted light, while exhibiting good diffraction uniformity. In other words, Figure 3A The transition grating region FG and Figure 4A The FG1 folding grating can have similar optical effects and offers good design freedom.

[0092] In some implementations, for example in Figure 1B In the illustrated super-grating unit FGC1 of the front-end transition grating partition FG1, the width W1 is approximately equal to the width W2, and the spacing G1 is approximately equal to the spacing G2. In some embodiments, the ratio of the period length TFG1 to the width W1 is in the range of 2.6 to 6.2, the ratio of the period length TFG1 to the spacing G1 is in the range of 2.6 to 7, the ratio of the width W1 to the width W2 may be equal to 1 or in the range of 1 to 1.2, and the ratio of the spacing G1 to the spacing G2 is in the range of 0.8 to 1.2.

[0093] In some implementations, for example Figure 1B In the illustrated metagrating unit FGC of the rear-end folding grating section FG2, the width W1 is greater than the width W2, and the spacing G1 is not equal to the spacing G2. In some embodiments, the ratio of the period length TFG to the width W1 is in the range of 4 to 6, the ratio of the period length TFG to the spacing G1 is in the range of 2 to 3.6, the ratio of the width W1 to the width W2 is in the range of 1.02 to 3.4, and the ratio of the spacing G1 to the spacing G2 is in the range of 0.8 to 1.6. In some embodiments, the rear-end folding grating section FG2 is designed to have a diffraction efficiency of less than 0.2 at a total internal reflection angle between 32 and 53 degrees.

[0094] In some implementations... Figure 1B The front-end transition grating partition FG1, the rear-end transition grating partition FG2, and the multiple transition grating partitions in between (not shown) can have the same super-gloss unit FGC design.

[0095] Please refer to Figure 5A . Figure 5A The super-grate unit OGC1 of the radiant grating partition OG1 is illustrated according to one or more embodiments of the present invention. Figure 5A In this configuration, the first grating 242 is located on the boundary of the super-grating unit OGC1. Within the period length TOG1 of the super-grating unit OGC1, the first grating 242 is aligned in the arrangement direction DA (e.g., Figure 1BThe first grating 242 has a width W1 in the Y direction. The second grating 243 is spaced apart from the second grating 243 by a spacing G1 in the arrangement direction DA. The second grating 243 has a width W2 in the arrangement direction DA. The second grating 243 is spaced apart from the boundary of the super-grating unit OGC1 by a spacing G2 in the arrangement direction DA. In some embodiments, such as... Figure 5A As shown, the width W1 is equal to the width W2, and the spacing G1 is greater than the spacing G2. Thus, multiple meta-grating units OGC1 are arranged periodically in the arrangement direction DA with a period length TOG1, forming the output grating partition OG1.

[0096] Figure 5B Drawing for Figure 5A The diagram illustrates the relationship between the transmitted or reflected diffracted light of different orders and the diffraction efficiency for different incident angles corresponding to the output grating section OG1. Figure 5B The horizontal axis corresponds to the angle of incidence, in degrees. Figure 5B The vertical axis corresponds to the diffraction efficiency, which is expressed in arbitrary units (au). Figure 5B Curves 0R, 1R, and 2R correspond to 0th, 1st, and 2nd order reflected diffracted light, respectively, while curve 1T corresponds to 1st order transmitted diffracted light. Figure 5B In this study, the diffraction efficiency of 0th-order reflected diffracted light is greater than that of 1st and 2nd-order reflected diffracted light and 1st-order transmitted diffracted light. Furthermore, the diffraction efficiency of 1st-order transmitted diffracted light is greater than that of 1st-order reflected diffracted light, thus reducing the occurrence of eye glow.

[0097] Please refer to Figure 6A . Figure 6A The super-grate unit OGC1 of the radiative grating partition OG1 is illustrated according to one or more embodiments of the present invention. Compared to Figure 5A The output grating section OG1, in Figure 6A The period length TOG1 of the super-grate unit OGC1 of the output grating partition OG1 is the same, the width W1 and width W2 are increased, the width W1 is greater than the width W2, and the spacing G1 and spacing G2 are decreased. Figure 6B Drawing for Figure 6A The diagram illustrates the relationship between the transmitted or reflected diffracted light of different orders and diffraction efficiency for different incident angles in the output grating section OG1. Figure 6B Even so, it can still ensure that within a specific incident angle range, the diffraction efficiency of the 0th order reflected diffracted light is greater than that of the 1st and 2nd order reflected diffracted light and the 1st order transmitted diffracted light.

[0098] In some embodiments, in the metagrating unit OGC1 of the output grating partition OG1, the width W1 is approximately equal to the width W2, and the spacing G1 is approximately equal to the spacing G2. In some embodiments, the ratio of the period length TOG1 to the width W1 is in the range of 3.8 to 12, the ratio of the period length TOG1 to the spacing G1 is in the range of 2.3 to 3.9, the ratio of the width W1 to the width W2 is equal to 1 or in the range of 1 to 1.4, and the ratio of the spacing G1 to the spacing G2 is in the range of 1 to 10. In some embodiments, the width W1 is smaller than the spacing G1.

[0099] Please refer to Figure 7A . Figure 7A The super-grate cell OGCM of the outgoing grating partition OGM is illustrated according to one or more embodiments of the present invention. The outgoing grating partition OGM is in Figure 1B Multiple intermediate exit grating sections OGM between exit grating section OG1 and exit grating section OG5. For example, an intermediate exit grating section OGM could be... Figure 1B The illustrated output grating sections are OG2, OG3, or OG4. Figure 7A In this configuration, the first grating 242 is located on the boundary of the super-grating unit OGCM. Within the period length TOGM of the super-grating unit OGCM, the first grating 242 is aligned in the alignment direction DA (e.g., Figure 1B The first grating 242 has a width W1 in the Y direction. The first grating 242 is spaced from the second grating 243 by a spacing G1 in the arrangement direction DA. The second grating 243 has a width W2 in the arrangement direction DA. The second grating 243 is spaced from the boundary of the super-gloss grating unit OGCM by a spacing G2 in the arrangement direction DA. In some embodiments, such as... Figure 7A As shown, the width W1 is greater than the width W2, and the spacing G1 is greater than the spacing G2. Thus, multiple super-gloss units OGCM are arranged periodically in the arrangement direction DA with a period length TOGM, forming the output grating partition OGM.

[0100] Figure 7B Drawing for Figure 7A The diagram illustrates the relationship between the transmitted or reflected diffracted light of different orders and diffraction efficiency for different incident angles corresponding to the output grating OGM. Figure 7B The horizontal axis corresponds to the angle of incidence, in degrees. Figure 7B The vertical axis corresponds to the diffraction efficiency, which is expressed in arbitrary units (au). Figure 7B Curves 0R, 1R, and 2R correspond to 0th, 1st, and 2nd order reflected diffracted light, respectively, while curve 1T corresponds to 1st order transmitted diffracted light. Figure 7B In this context, the diffraction efficiency of 0th-order reflected diffracted light is greater than that of 1st and 2nd-order reflected diffracted light and 1st-order transmitted diffracted light.

[0101] Please refer to Figure 8A . Figure 8A The super-grate unit OGCM of the radiated grating partition OGM is illustrated according to one or more embodiments of the present invention. Figure 7A The output grating partition OGM and Figure 8A The output grating partition OGM can correspond to Figure 1B The differences lie in the multiple output grating sections OG2, OG3, and OG4. For example, Figure 7A The output grating partition OGM can correspond to Figure 1B The output grating partition OG3. Figure 8A The output grating partition OGM can correspond to Figure 1B The output grating section OG4. Compared to Figure 7A The output grating partition OGM, in Figure 8A The period length TOG1 of the super-grate unit OGC1 of the output grating partition OG1 is the same, the width W1 increases, the width W2 decreases, the difference between the widths W1 and W2 increases, and the spacing G1 is smaller than the spacing G2. Figure 8B Drawing for Figure 8A The diagram illustrates the relationship between the transmitted or reflected diffracted light of different orders and diffraction efficiency for different incident angles in the output grating section OG1. Figure 8B In this process, it is still possible to ensure that within a specific incident angle range, the diffraction efficiency of the 0th order reflected diffracted light is greater than that of the 1st and 2nd order reflected diffracted light and the 1st order transmitted diffracted light, but the diffraction efficiency of the 2nd order reflected diffracted light and the 1st order transmitted diffracted light increases significantly.

[0102] In some implementations, in the output grating partition OGM (e.g. Figure 1B In the illustrated super-grating units OGCM of the output grating partitions OG2, OG3, and OG4, the width W1 is greater than the width W2, and the spacing G1 is not equal to the spacing G2. In some embodiments, the ratio of the period length TOGM to the width W1 is in the range of 1.5 to 5.3, the ratio of the period length TOGM to the spacing G1 is in the range of 2.5 to 11, the ratio of the width W1 to the width W2 is approximately equal to 1.1 or in the range of 1.1 to 3, and the ratio of the spacing G1 to the spacing G2 is in the range of 0.7 to 2.2.

[0103] Please refer to Figure 9A . Figure 9A According to one or more embodiments of the present invention, the radiated grating partition OG5 is drawn (e.g., Figure 1B The super-grate unit OGC5 in the output grating partition OG5. Figure 9AIn this configuration, the first grating 242 is located on the boundary of the super-grating unit OGC5. Within the period length TOG5 of the super-grating unit OGC5, the first grating 242 is aligned in the arrangement direction DA (e.g., Figure 1B The first grating 242 has a width W1 in the Y direction. The second grating 243 is spaced apart from the second grating 243 by a spacing G1 in the arrangement direction DA. The second grating 243 has a width W2 in the arrangement direction DA. The second grating 243 is spaced apart from the boundary of the super-grating unit OGC5 by a spacing G2 in the arrangement direction DA. In some embodiments, such as... Figure 9A As shown, the width W1 is greater than the width W2, and the spacing G1 is greater than the spacing G2. Thus, multiple super-grate units OGC5 are arranged periodically in the arrangement direction DA with a period length TOG5, forming the output grating partition OG5.

[0104] Figure 9B Drawing for Figure 9A The diagram illustrates the relationship between the transmitted or reflected diffracted light of different orders and diffraction efficiency for different incident angles corresponding to the output grating OGM. Figure 9B The horizontal axis corresponds to the angle of incidence, in degrees. Figure 9B The vertical axis corresponds to the diffraction efficiency, which is expressed in arbitrary units (au). Figure 9B Curves 0R, 1R, and 2R correspond to 0th, 1st, and 2nd order reflected diffracted light, respectively, while curve 1T corresponds to 1st order transmitted diffracted light. Figure 9B In this context, the diffraction efficiency of 1st-order transmitted diffracted light is greater than that of 0th-order, 1st-order, and 2nd-order reflected diffracted light.

[0105] In some embodiments, in the metagrating unit OGC5 of the output grating partition OG5, the width W1 is greater than the width W2, and the spacing G1 is greater than the spacing G2. In some embodiments, the ratio of the period length TOG5 to the width W1 is in the range of 2.4 to 2.8, the ratio of the period length TOG5 to the spacing G1 is in the range of 2.5 to 3.2, the ratio of the width W1 to the width W2 is approximately equal to 2.1 or in the range of 2.1 to 3, and the ratio of the spacing G1 to the spacing G2 is in the range of 2.5 to 3.1.

[0106] In some implementations, the outgoing grating partition OG1 can be considered as the front-end outgoing grating partition OG1, and the outgoing grating partition OG5 can be considered as the rear-end outgoing grating partition OG5. One or more outgoing grating partitions OGM may be included between the front-end outgoing grating partition OG1 and the rear-end outgoing grating partition OG5. Examples, but not limited to these, include... Figure 1BAs shown, the output grating partitions OG1 and OG5 include three output grating partitions OG2, OG3, and OG4. In some embodiments, the width W1 of the first grating 252 within a corresponding period length (e.g., any one of period lengths TOG1, TOGM, and TOG5) increases from the front output grating partition OG1 to the rear output grating partition OG5. For example, the width W1 of the first grating 252 of the exit grating partition OG2 is greater than the width W1 of the first grating 252 of the front exit grating partition OG1, the width W1 of the first grating 252 of the exit grating partition OG3 is greater than the width W1 of the first grating 252 of the exit grating partition OG2, the width W1 of the first grating 252 of the exit grating partition OG4 is greater than the width W1 of the first grating 252 of the exit grating partition OG3, and the width W1 of the first grating 252 of the rear exit grating partition OG5 is greater than the width W1 of the first grating 252 of the exit grating partition OG4.

[0107] Thus, the outgoing grating partition OG1, outgoing grating partition OGM (e.g., outgoing grating partitions OG2, OG3 and OG4) and outgoing grating partition OG5 can have different diffraction characteristics, thereby achieving pupil expansion in one dimension.

[0108] In one or more embodiments, the period length (e.g., any one of the super-gated grating units IGC of the incident grating region IG, the super-gated grating units FGC of the transition grating region FG (which may include transition grating partitions FG1 and FG2), and the super-gated grating units OGC of the multiple exit grating partitions OG1, OG2, OG3, OG4, and OG5 of the exit grating region OG) is in the range of 200 nm to 1600 nm.

[0109] Please refer to Figure 10 . Figure 10 A top view of an optical waveguide structure 200' is illustrated as an example of one or more embodiments of the present invention. Compared to Figure 1B Optical waveguide structure 200, in Figure 10 In the optical waveguide structure 200', if the multiple gratings 241 of the outgoing grating region OG are arranged along the Y direction, the multiple gratings 221 of the incoming grating region IG are arranged in a direction different from the X direction (for example, arranged in a direction that is rotated 60 degrees counterclockwise relative to the Y direction), and the multiple gratings 221 of the turning grating region FG are arranged in a direction different from the X direction or the Y direction (for example, arranged in a direction that is rotated 120 degrees counterclockwise relative to the Y direction).

[0110] Please refer to Figures 11A to 11F . Figures 11A to 11EAccording to various embodiments of the present invention, multiple super-grate units GC1, GC2, GC3, GC4, and GC5 are illustrated respectively. Figure 11F Draw Figures 11A to 11E A cross-section of a plurality of metaglossary units GC1, GC2, GC3, GC4, and GC5 is shown. Each of the metaglossary units GC1, GC2, GC3, GC4, and GC5 includes a plurality of gratings 251, and each grating 251 includes one or more first gratings 252 and one or more second gratings 253. In one or more embodiments of the present invention, each of the metaglossary units GC1, GC2, GC3, GC4, and GC5 can be used as any of the incident metaglossary unit IGC, the transition metaglossary unit FGC, and the exit metaglossary unit OGC. The first grating 252 of the metaglossary units GC1, GC2, GC3, GC4, and GC5 can be used as the first grating (e.g., first grating 222, 232, or 242) in any of the incident metaglossary unit IGC, the transition metaglossary unit FGC, and the exit metaglossary unit OGC. The second grating 253 of the super-gloss units GC1, GC2, GC3, GC4, and GC5 can be used as the second grating (e.g., second grating 223, 233, or 243) in any of the incident super-gloss unit IGC, the transition super-gloss unit FGC, and the exit super-gloss unit OGC. The alignment direction DA can be considered as the corresponding alignment direction of the gratings (e.g., gratings 221, 222, or 223) in the incident super-gloss unit IGC, the transition super-gloss unit FGC, and the exit super-gloss unit OGC.

[0111] exist Figure 11A In the illustrated super-grate unit GC1, the first grating 252 is rectangular, and the second grating 253 includes rectangular sub-gratings separated in one direction of the vertical alignment direction DA. Figure 11F Draw Figure 11A The cross-sectional view along line segment C1-C1', with the cross-sections arranged parallel to the direction DA.

[0112] exist Figure 11B In the illustrated super-gloss unit GC2, the first gloss 252 includes rectangular sub-glosses separated in one direction of the vertical alignment direction DA, and the second gloss 253 includes elongated rectangular sub-glosses separated in one direction of the vertical alignment direction DA. Figure 11F Draw Figure 11B The cross-sectional view along line segment C2-C2', with the cross-sections arranged parallel to the direction DA.

[0113] exist Figure 11C In the illustrated super-grating unit GC3, the first grating 252 includes a rectangular sub-grating separated in one direction of the vertical alignment direction DA, and the second grating 253 includes a square sub-grating separated in one direction of the vertical alignment direction DA. Figure 11F Draw Figure 11C The cross-sectional view along line segment C3-C3', with the cross-sections arranged parallel to the direction DA.

[0114] exist Figure 11D In the illustrated super-grating unit GC4, the first grating 252 includes rectangular sub-gratings separated in one direction of the vertical alignment direction DA, and the second grating 253 is rectangular. Figure 11F Draw Figure 11D The cross-sectional view along line segment C4-C4', with the cross-sections arranged in parallel directions DA.

[0115] exist Figure 11E In the illustrated super-grating unit GC5, the first grating 252 includes an elliptical grating with unequal width in one direction of the parallel alignment direction DA, and the second grating 253 includes two elliptical sub-gratings separated in one direction of the perpendicular alignment direction DA, and the two elliptical sub-gratings of the second grating 253 have unequal width and different shapes in one direction of the parallel alignment direction DA. Figure 11F Draw Figure 11E The cross section along line segment C5-C5' is parallel to the direction DA.

[0116] In one or more embodiments of the present invention Figures 11A to 11E The gratings 252 and 253 in the illustrated super-grating units GC1, GC2, GC3, GC4, and GC5 have the same shape on the cross-sections corresponding to the line segments C1-C1', C2-C2', C3-C3', C4-C4', and C5-C5', and can be equivalently regarded as the same super-grating unit GC. For example... Figure 11F As shown, in the super-grating unit GC, the shape of the first grating 252 in cross-section is aligned with the boundary of the period length TGC. The shape of the first grating 252 in cross-section has a width W1. The shape of the second grating 253 in cross-section has a width W2. There is a spacing G1 between the two-dimensional projection structure of the first grating 252 and the shape of the second grating 253 in cross-section. The shape of the second grating 253 in cross-section is spaced apart from the other boundary of the period length TGC by a spacing G2. In one or more embodiments, the width W1 is greater than or equal to the width W2, and the ratio of the spacing G1 to the spacing G2 is in the range of 0.1 to 10. In one or more embodiments, the width W1 is greater than the width W2, and the ratio of the spacing G1 to the spacing G2 is in the range of 0.7 to 10.

[0117] Since the first grating 252 and the second grating 253 of grating 251 are periodically arranged along the arrangement direction DA with a period length TGC, different metagloss units with the same period length can be used to describe the same arrangement of grating 251. For example, it can be... Figure 11FThe super-gloss unit GC in the first grating is translated by a distance of width W1 and spacing G1 along the arrangement direction DA to define another super-gloss unit with a period length TGC and whose boundaries are aligned with the second grating 253. This starting point in the super-gloss unit of the second grating 253 sequentially includes the second grating 253, spacing G2, first grating 252, and spacing G1 along the arrangement direction DA, wherein the width W2 is less than or equal to the width W1, and the ratio of spacing G1 to spacing G2 is in the range of 0.1 to 10. In one or more embodiments, the width W2 is less than the width W1, and the ratio of spacing G1 to spacing G2 is in the range of 0.7 to 10. This starting point, after the periodic arrangement of the super-gloss units of the second grating 253, can describe a... Figure 11F The periodic arrangement of the super-inverted grating units GC in the image describes the same arrangement as that of the grating 251. Furthermore, any periodic arrangement can describe the same... Figure 11F The super-grate units GC described in the invention have the same arrangement as the super-grate units 251, and are also included in this invention.

[0118] In one or more embodiments of the present invention, since the parallel gratings 251 of the meta-grating units GC1, GC2, GC3, GC4, and GC5 can be equivalently regarded as cross-sections... Figure 11F The super-grating units GC shown, GC1, GC2, GC3, GC4, and GC5, can produce similar modulation characteristics when modulating the diffraction efficiency of transmitted and reflected diffracted light of different orders. In some embodiments, such as Figure 11F As shown, the period length TGC, width W1, width W2, spacing G1, and spacing G2 of the metamorphic grating unit GC can satisfy... Figure 2A , Figure 3A , Figure 4A , Figure 5A , Figure 6A , Figure 7A , Figure 8A and Figure 9A The period length TGC, width W1, width W2, spacing G1, and spacing G2 of any of the metaglossary units (e.g., metaglossary units IGC, FGC, OGC1, OGCM, or OGC5) are set to achieve similar diffraction modulation characteristics for reflected and transmitted diffracted light of different orders. In one or more embodiments of the present invention, each of the metaglossary units GC1, GC2, GC3, GC4, and GC5 can be used as any of the incident metaglossary unit IGC, the transition metaglossary unit FGC, and the exit metaglossary unit OGC.

[0119] Please refer to Figures 12 to 15 . Figures 12 to 15Multiple metagloss units GC6, GC7, GC8, GC9, and GC10 are illustrated according to various embodiments of the present invention. Each of the metagloss units GC6, GC7, GC8, GC9, and GC10 includes multiple gratings 251, and each grating 251 includes one or more first gratings 252 and one or more second gratings 253. In one or more embodiments of the present invention, each of the metagloss units GC6, GC7, GC8, GC9, and GC10 can be used as any of the incident metagloss unit IGC, the transition metagloss unit FGC, and the exit metagloss unit OGC. The first grating 252 of the metagloss units GC6, GC7, GC8, GC9, and GC10 can be used as the first grating (e.g., first grating 222, 232, or 242) in any of the incident metagloss unit IGC, the transition metagloss unit FGC, and the exit metagloss unit OGC. The second grating 253 of the super-gloss units GC6, GC7, GC8, GC9, and GC10 can be used as the second grating (e.g., second grating 223, 233, or 243) in any of the incident super-gloss unit IGC, the transition super-gloss unit FGC, and the exit super-gloss unit OGC. The alignment direction DA can be considered as the corresponding alignment direction of the gratings (e.g., gratings 221, 222, or 223) in the incident super-gloss unit IGC, the transition super-gloss unit FGC, and the exit super-gloss unit OGC.

[0120] Figure 12 The first grating 252 of the super-grating unit GC6 includes a first grating portion 2521 and a second grating portion 2522 above the first grating portion 2521. The second grating 253 of the super-grating unit GC6 includes a first grating portion 2531 and a second grating portion 2532 above the first grating portion 2531. In some embodiments, the first grating portions 2521 and 2531 have the same grating material, and the second grating portions 2522 and 2532 have the same grating material, but the grating materials of the first grating portions 2521 and 2531 are different from the grating materials of the second grating portions 2522 and 2532. In some embodiments, the refractive index of the grating material of the first grating portions 2521 and 2531 is different from the refractive index of the grating material of the second grating portions 2522 and 2532. Figure 12In this embodiment, the second grating portions 2522 and 2532 have different lengths in the Z direction. In some embodiments, the first grating 252 and the second grating 253 can be formed by the same etching process. For example, forming the first grating 252 and the second grating 253 may include forming grating material layers of the first grating portions 2521 and 2531 on a substrate; recessing the grating material layers of the first grating portions 2521 and 2531 such that the grating material layers at positions corresponding to the first grating portion 2531 are recessed; forming grating material layers of the second grating portions 2522 and 2532 on top of the grating material layers of the first grating portions 2521 and 2531, and polishing the grating material layers of the second grating portions 2522 and 2532; and patterning the grating material layers of the first grating portions 2521 and 2531 and the grating material layers of the second grating portions 2522 and 2532 to form the first grating 252 and the second grating 253. Thus, in the Z direction, the length of the second grating portion 2522 of the first grating 252 is less than the length of the second grating portion 2532 of the second grating 253.

[0121] Figure 13 The first grating 252 of the super-grating unit GC7 includes a first grating portion 2521 and a second grating portion 2522 above the first grating portion 2521. The second grating 253 of the super-grating unit GC7 includes a first grating portion 2531 and a second grating portion 2532 above the first grating portion 2531. Compared to Figure 12 The GC6 super-innovative grating unit, in Figure 13 In the super-gloss unit GC7, in the Z direction, the second grating portion 2522 of the first grating 252 and the second grating portion 2532 of the second grating 253 have the same length.

[0122] Figure 14 The first grating 252 and the second grating 253 of the super-sensitive grating unit GC8 have different refractive indices from top to bottom in the Z direction. In some embodiments, for example but not limited thereto, the first grating 252 and the second grating 253 can be formed via a grating material layer formed on the substrate 210, and before the patterned grating material layer forms the first grating 252 and the second grating 253, the grating material layer can be doped with different concentrations from top to bottom, so that the formed first grating 252 and the second grating 253 have different refractive indices from top to bottom.

[0123] Figure 15 The first grating 252 and the second grating 253 of the super-intelligence grating unit GC9 have unequal widths from top to bottom in the arrangement direction DA, but can still be periodically arranged in the arrangement direction DA to modulate the diffraction efficiency of light.

[0124] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be defined by the appended claims.

[0125] It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the embodiments of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, the present invention is intended to cover modifications and variations thereof, provided they fall within the appended scope of protection.

Claims

1. An optical waveguide structure, characterized in that, Include: substrate; An incident grating region is located on the substrate and includes a plurality of periodically arranged incident super-grating units; A transition grating region, located on the substrate and comprising a plurality of periodically arranged transition meta-grating units, wherein the incident grating region and the transition grating region are arranged along a first direction; and An emission grating region, located on the substrate, includes multiple emission grating sections, wherein the emission grating region is located on one side of the transition grating region, and the transition grating region and the emission grating region are arranged along a second direction different from the first direction. Each of the multiple emission grating sections includes multiple periodically arranged emission super-grating units. Each of the plurality of incident metamorphic grating units, the plurality of folding metamorphic grating units, and the plurality of exiting metamorphic grating units includes a first grating and a second grating. In the period length of each of the plurality of incident metagloss units, the plurality of folding metagloss units, and the plurality of exiting metagloss units The first grating has a first shape in cross-section, and the second grating has a second shape in cross-section. The first shape is located on a first boundary of the period length and has a first width; The second shape has a second width; The first shape and the second shape have a first spacing; as well as The second shape is a second distance from the second boundary of the period length, the first width is greater than or equal to the second width, and the ratio of the first distance to the second distance is in the range of 0.1 to 10.

2. The optical waveguide structure as described in claim 1, characterized in that, The plurality of first gratings and the plurality of second gratings of the plurality of incident metaglosses, the plurality of folding metaglosses, and the plurality of exit metaglosses have the same height on their plurality of top surfaces.

3. The optical waveguide structure as described in claim 1, characterized in that, In each of the plurality of incident metagloss units, the plurality of folding metagloss units, and the plurality of exiting metagloss units, when the first width is greater than the second width, the ratio of the first spacing to the second spacing is in the range of 0.7 to 10.

4. The optical waveguide structure as described in claim 1, characterized in that, In one of the plurality of incident metagloss grating units, the plurality of folding metagloss grating units, and the plurality of exiting metagloss grating units, the first grating and the second grating include a plurality of sub-gratings that are separated from each other in a direction perpendicular to the cross-section.

5. The optical waveguide structure as described in claim 1, characterized in that, Each of the plurality of first gratings and the plurality of second gratings includes: The first grating portion is located on the substrate; and A second grating portion is located on the first grating portion, wherein the refractive index of the first grating portion is different from the refractive index of the second grating portion.

6. The optical waveguide structure as described in claim 5, characterized in that, The length of the second grating portion of one of the plurality of first gratings is different from the length of the second grating portion of one of the plurality of second gratings.

7. The optical waveguide structure as described in claim 1, characterized in that, In one of the plurality of incident super-gloss grating units in the incident grating region The first width is greater than the second width; The first spacing is greater than the second spacing; The ratio of the period length of the plurality of incident metagaze units to the first width is in the range of 2.4 to 2.8; The ratio of the period length of the plurality of incident metagaze units to the first spacing is in the range of 2.7 to 3.9; The ratio of the first width to the second width is in the range of 2.7 to 3.8; and The ratio of the first spacing to the second spacing is in the range of 1.1 to 2.

8.

8. The optical waveguide structure as described in claim 1, characterized in that, The transition grating region includes a front transition grating section, a rear transition grating section, and a plurality of intermediate transition grating sections between the front and rear transition grating sections, wherein in one of the plurality of transition super-grating units of the front transition grating section... The first width is equal to the second width; The first spacing is equal to the second spacing; The ratio of the period length to the first width of the plurality of folded metagrating units in the front-end folded grating partition is in the range of 2.6 to 6.2; The ratio of the period length of the plurality of folded super-grate units in the front-end folded grating partition to the first pitch is in the range of 2.6 to 7; The ratio of the first width to the second width is equal to 1 or is in the range of 1 to 1.2; and The ratio of the first spacing to the second spacing is in the range of 0.8 to 1.

2.

9. The optical waveguide structure as described in claim 1, characterized in that, The transition grating region includes a front transition grating section, a rear transition grating section, and a plurality of intermediate transition grating sections between the front and rear transition grating sections, wherein in one of the plurality of transition super-grating units of the rear transition grating section... The first width is greater than the second width; The first spacing is not equal to the second spacing; The ratio of the period length to the first width of the plurality of folded super-gloss units in the rear-end folded grating partition is in the range of 4 to 6; The ratio of the period length of the plurality of folded metagrating units in the rear-end folded grating partition to the first pitch is in the range of 2 to 3.6; The ratio of the first width to the second width is in the range of 1.02 to 3.4; and The ratio of the first spacing to the second spacing is in the range of 0.8 to 1.

6.

10. The optical waveguide structure as described in claim 1, characterized in that, The plurality of emission grating partitions in the emission grating region include a front emission grating partition, a rear emission grating partition, and one or more intermediate emission grating partitions between the front emission grating partition and the rear emission grating partition, wherein in one of the plurality of emission super-gloss grating units in the front emission grating partition... The first width is equal to the second width; The first spacing is equal to the second spacing; The ratio of the period length to the first width of the plurality of emission super-gloss grating units in the front-end emission grating partition is in the range of 3.8 to 12; The ratio of the period length of the plurality of emission super-gloss grating units in the front-end emission grating partition to the first spacing is in the range of 2.3 to 3.9; The ratio of the first width to the second width is equal to 1 or is in the range of 1 to 1.4; and The ratio of the first spacing to the second spacing is in the range of 1 to 10.

11. The optical waveguide structure as described in claim 1, characterized in that, The plurality of emission grating partitions in the emission grating region include a front emission grating partition, a rear emission grating partition, and one or more intermediate emission grating partitions between the front emission grating partition and the rear emission grating partition, wherein in one of the plurality of emission super-gloss grating units of the one or more intermediate emission grating partitions, The first width is greater than the second width; The first spacing is not equal to the second spacing; The ratio of the period length to the first width of the plurality of emission super-gloss grating units in the one or more intermediate emission grating sections is in the range of 1.5 to 5.3; The ratio of the period length of the plurality of emission super-gloss grating units in the one or more intermediate emission grating sections to the first spacing is in the range of 2.5 to 11; The ratio of the first width to the second width is equal to 1.1 or is in the range of 1.1 to 3; and The ratio of the first spacing to the second spacing is in the range of 0.7 to 2.

2.

12. The optical waveguide structure as described in claim 1, characterized in that, The plurality of emission grating partitions in the emission grating region include a front emission grating partition, a rear emission grating partition, and one or more intermediate emission grating partitions between the front emission grating partition and the rear emission grating partition, wherein in one of the plurality of emission super-gloss grating units in the rear emission grating partition... The first width is greater than the second width; The first spacing is greater than the second spacing; The ratio of the period length to the first width of the plurality of emission super-gloss units in the rear emission grating partition is in the range of 2.4 to 2.8; The ratio of the period length of the plurality of emission super-gloss grating units in the rear emission grating partition to the first spacing is in the range of 2.5 to 3.2; The ratio of the first width to the second width is equal to 2.1 or is in the range of 2.1 to 3; and The ratio of the first spacing to the second spacing is in the range of 2.5 to 3.

1.

13. An optical waveguide structure, characterized in that, Include: substrate; An incident grating region is located on the substrate and includes a plurality of periodically arranged incident super-grating units; A transition grating region, located on the substrate and comprising a plurality of periodically arranged transition meta-grating units, wherein the incident grating region and the transition grating region are arranged along a first direction; and An emission grating region, located on the substrate, includes multiple emission grating sections, wherein the emission grating region is located on one side of the transition grating region, and the transition grating region and the emission grating region are arranged along a second direction different from the first direction. Each of the multiple emission grating sections includes multiple periodically arranged emission super-grating units. Each of the plurality of incident super-gloss grating units, the plurality of folding super-gloss grating units, and the plurality of exiting super-gloss grating units includes a first grating and a second grating, and the plurality of top surfaces of the plurality of first gratings and the plurality of second gratings of the plurality of incident super-gloss grating units, the plurality of folding super-gloss grating units, and the plurality of exiting super-gloss grating units have the same height.

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